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Building Blocks of Life

Introduction

Deep in space, dust is diffracting light, and providing clues to the materials it is passing through, materials that have existed since the early days in the 'life' of the universe.

There happens to be a strong correlation between patterns of light absorption by some dust clouds and that made by small hollow spheres the size of common (earthly) bacteria. This led Fred Hoyle and N. Chandra Wickramasinghe to propose the theory of Panspermia, where life was seeded on earth from space (1 Klyce). While this idea has been ridiculed, this correlation still exists. 

One alternate explanation may be that this is a coincidence caused by a similar evolution of bacteria-like organisms, the dust of a life that evolved on (an)other planet(s) from similar chemical backgrounds and where the systems have met some catastrophic end (star system goes nova, collisions, etc). The universe is about 3 times older than the earth, so there is plenty of time for life to have evolved on other planets in other system, provided that the necessary conditions and material were available: the only caveat being what would cause such an improbable coincidence of development.

The existence of other suitable planets seems less and less of a question as we continue to discover more and more planets around other stars, but for such similar life to have such a similar chemical basis there would have to be some method of disbursing the basic chemical compounds used in the formation of life through space. The method does not need to be organic (life based): stellar novas are the #1 basic method of disbursing chemical elements into space after the fusion of hydrogen into those elements during the life of the star. These events are catastrophic certainly, but as the expelled gases expand and cool there is opportunity for all kinds of chemical combinations to take place, easily allowing the formation of even complex molecules. Perhaps there is just some unknown astro-chemical preference for the formation of carbon based life precursor molecules and that they are common throughout the universe. Perhaps the dust balls noted by Hoyle and Wickramasinghe are the signatures of large 'organic' hydrocarbon molecules we are unfamiliar with.

Speculation is fun for all, but what evidence do we have to support such seemingly far-fetched science fiction? Surprisingly, the evidence is substantial. From {the farthest reaches of the Universe}, across own solar system, and to the farthest reaches of our own Earth, evidence of pre-biotic formation of life surround us. This paper will walk you through the evidence, painting a picture of how life could have come to form on Earth.

Evidence

Evidence comes from a number of sources.

From The Universe

So far over 130 different molecules have been discovered in interstellar clouds (2 anon 2004). Most contain a small number of atoms, and only a few molecules with seven or more atoms have been found so far. The most abundant family of molecules in the interstellar medium, after molecular hydrogen and carbon monoxide, are the polycyclic aromatic hydrocarbon (PAH) molecules. These molecules contain about 10% of all the interstellar carbon (3 Bregman & Temi).

In the farthest depths of the universe polycyclic aromatic hydrocarbon (PAH) molecules have been found by the Spitzer Space Telescope, 10 billion light-years away (4 Hill 2005). Other deep space organic compounds that have already been found are the 7-atom vinyl alcohol (5 anon 2001), the 8-atom molecule propenal and the 10-atom molecule propanal (2 anon 2004), all in interstellar clouds of dust and gas near the center of the Milky Way Galaxy, all some 24,000 light-years away - a distance so far, the molecules could not have come from earth.

Finding bigger molecules might be more difficult, as we have to know what the 'signatures' of those particles are. This is difficult because those particles need to be modeled first to see what their diffraction patterns would be, and we would have to know what the molecules were to model them. This would be similar to the difficulties encountered by Hoyle and Wickramasinghe in matching the dust spectrum to dried bacteria (1 Klyce) and by Rosalind Franklin in unraveling DNA patterns and other folded proteins with crystallography before their structure was fully understood (6 anon).

A little closer to home, the signatures of polycyclic aromatic hydrocarbon (PAH) molecules were found again, this time in the vicinity of a protostellar source, S140 (3 Bregman & Temi). The source, about 3,000 light-years away, is a star in the process of forming. This fact provides more evidence that this hydro-carbon based material was already available at this point of the star's, stage of formation. By extension, it also means that the material was available at the time of any planet’s formation.

Traditionally chemists have referred to these compounds as organic molecules because of their association with organic processes. With these discoveries of such molecules in outer space and, presumably, from non-living sources, it seems that a new paradigm is needed. I will refer to these cosmic based complex hydro-carbon compounds hereafter as "Pre-Organic Compounds", or POCs.

From The Solar System

In the immediate stellar neighborhood we have data from our gas giants and their moons. The IRIS-Voyager infrared spectrometer detected prebiotic molecules on Titan as well as complex organic molecules on Jupiter and Saturn. The Cassini satellite found an organic "factory" of hydrocarbons in the upper atmosphere of Titan (7 Martinez 2005). Carbonaceous material has also been observed in the immediate surroundings of Comet Halley's nucleus, implying these materials are also readily available in the OORT cloud surrounding the planets (8 Encrenaz 1986). These findings, tells us that such POCs are formed in an interstellar medium by non-living procedures. Furthermore, even if they are not uniformly available in the early formation of the system, they are certainly available for transport from such locations where they are available to any planets in the stellar system.

Moving farther in, we have detected a host of POCs on meteors. Mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons (9 Pizzarello et al 2001) have been found. In addition, hollow, bubble-like hydrocarbon globules, similar to early membraneous formations (10 Watson 2002), and "polyols," components of the nucleic acids RNA and DNA, constituents of cell membranes and cellular energy sources (11 Koczor 2001 & 12 Cooper et al 2001) have been detected in material from meteors as well.

Meteors could also be a source of elements that would otherwise be rare on the surface of the early earth. The steps taken in creating DNA or RNA (one of a number of possible precursors to the advent of DNA on Earth) are unclear. Most of the necessary raw materials and elements for forming RNA-like molecules are readily available at Earth’s surface - except for rare elements like phosphorus. At least one study argues that meteorites could have provided the rare elements needed by the early self replicating molecules in readily accessible forms like P2O7, one of the more biochemically useful forms of phosphate, similar to what's found in ATP (13 Reddy 2004). Support for this also comes from the record of meteor bombardment of the moon, which indicates that meteors were much more common during the early days of this planet. There is also reason to believe there may also have been a peak of meteor activity just before the earliest known life appeared, some 3.9 to 3.8 billion years ago (14 Hartmann et al 2000 & 15 Ehrenfreund et al 2002).

The Earth Back Then

There have been experiments on what might have been happening outside the earth's atmosphere in conditions simulating the early solar system. Scientists made glycine, alanine and serine, three of the basic parts of proteins from which all life is made, by simulating conditions that are commonplace in interstellar space and shining ultraviolet light on deep-space-like "ices" (16 Burton 2002 & 17 anon 2002) - again pointing to a ready source of pre-formed amino acids from space and removing the necessity of their formation somewhere on earth. This is also beginning to stretch the definition of "Pre-Organic Compound" (POC) to it's limit, for amino acids are the molecules that living organisms are made from.

As we can see, these POC molecules may have formed outside of the earth. If these molecules did come to earth from space, the next question is what earth was like in those early days and what kind of existence was possible. This would have been before free oxygen (O2) was readily available in the atmosphere. While early models of the earth assumed a reducing atmosphere, recent modeling of the Earth's early atmosphere suggests more neutral conditions (e.g. H2O, N2, CO2) may have existed (15 Ehrenfreund et al 2002). Even so, most researchers still accept that O2 experienced a large increase near 2.3 billion years ago, long after life first evolved, and the evidence indicates that O2 was less than ~10-3 current levels during the Archean if not lower (18 Kasting & Pavlov 2001), so the earliest life form(s) were likely based on some other energy transfer system than one using free oxygen (ie some kind of anaerobic system).

The Earth Now

One way to determine possible environments and energy systems that were once on earth and that may have been involved in early life development we can look at what are called "extremeophiles" - archaic bacteria like organisms, living under what appears to us to be extreme conditions. The reasoning behind this is dual-pronged; first, these extreme environments may match, and even be the norm, in early-Earth conditions. Second, it is likely that any such remnant environment would also be inhabited by remnants of early life forms - forms such as these “extremeophiles.”

One area that may exhibit such properties is the deep ocean floor around the thermal vents, where life today is still a bizarre chemistry for organisms compared to what we know. Recently, simulating such conditions amino acids were combined into peptides (19 Simpson 1999), and the oldest evidence for life may be thermophile remnants in Greenland rocks that are 3.7 to 3.9 billion years old, where some researchers have concluded that the grains contained carbon of biological origin (20 Hart 2005). Similar research synthesized the critical compound pyruvic acid (CH3-CO-COOH) from CO in the presence of iron-sulphide at 250° C and pressures equivalent to a depth of 7 km within the rock (21 Earle 2000).

Another element that comes into play with these kinds of areas is radioactive energy and it's effect of the polymerization of larger molecules. The geological record includes widespread evidence for organic accretion and polymerization around radioactive mineral grains (22 Parnell 2003). This may have been a mechanism to help concentrate the necessary molecules in the same locations.

There are many types of anaerobic bacteria, but the real interest here is in the “Archaea” - a life form similar to bacteria but from a separate and earlier domain of life, and found in many extreme environments. Some Archaea, belonging to the methanogens (methane producing microorganisms), are found in cold deep sea sediments called methane seeps at 1,640 to 3,280 feet beneath the surface, where the pressure compresses methane and traps it in a lattice of water ice crystals to form gas hydrates at temperatures of 45 degrees Fahrenheit or even warmer, depending on the crystal structure and depth. (23 Siegel 2005). The Archaea found at the seeps were completely surrounded by sulfate reducing bacteria in a symbiotic relationship that utilized both methane and sulfates for energy (24 Ferdelman et al 2005).

From the Bottom Up

This gives us ideas of where the first forms of life may have developed, but to get to there from the chemicals and energy sources mentioned previously, we need to look at the simplest molecules that can be formed and then move up towards the more complex ones.

First off we have some peptides built out of existing amino acids under conditions similar to possible early earth conditions: under the hot, anaerobic, aqueous conditions of a setting with magmatic exhalations, amino acids are converted into peptides. Peptides were formed from phenylalanine, tyrosine, and glycine (25 Huber & Wächterhäuser 1998).

Next we turn to self-replicating molecule experiments. First, a self-replicating 32-amino-acid peptide can autocatalyse its own synthesis by accelerating the amino-bond condensation of 15- and 17-amino-acid fragments in solution (26 Kauffman 1996). Then there is the amino adenosine triacid ester (AATE) that replicates by attracting to one of its ends anester molecule, and to its other end an amino adenosine molecule. These molecules react to form another AATE. The "parent" and "child" AATE molecules then break apart and can go on to build still more AATE molecules (27 Mallove 1990).These experiments are such convincing demonstrations of self-replication by non-living molecules that even extremely skeptical organizations like AnswerInGenesis (AIG) do not dispute the formation of the phenylalanine, tyrosine, and glycine peptides (28 Sarfati) or that the AATE molecules formed new ones (29 Sarfati 2002).

Another experiment shows how cell-like membranes can be formed from common chemicals like calcium chloride, sodium carbonate, copper chloride, sodium iodide, hydrogen peroxide and starch and that they contain chemical reactions (30 Ball 2004), and another shows that these compounds are common in meteor "ices" and that the meteor compounds do form vesicles with the addition of water (31 Dworkin et al 2001).

Formation of amino acids by bacteria is also well documented, but researchers have cause a "new" amino acid to be formed by one, p-aminophenylalanine, or pAF (32 Suh 2003). This demonstrates that the 20 amino acids that are commonly used by all life on Earth are not necessarily special to the formation of life here. Instead, it is likely that they were just the most useful ones available at the time.

Finally, there is the evidence that viruses may be older than our commonly accepted life forms: coat proteins in all viral types that infect all three of the modern domains of life - Eukarya, Bacteria, and Archaea - have conformational similarities, despite the fact that the genetics underlying them are quite different. This implies a common "ancestor" for all these forms of viruses that predates the three domains of life over 3 billion years ago. These viruses could be remnants of a pre-DNA world that was based on RNA replication, remnants that have lost their individual ability to reproduce by adapting to use the replication methods of the DNA world (33 Rice et al 2004).

Conclusions

It seems to me that the building blocks needed for the beginning of life were plentiful, not just on Earth but in space in general and from the earliest of times. They have been around since long before even the Earth formed from the cosmic debris left behind by the life and death cycle of previous stars and planets, back to the beginning of time. These "seeds of life" no doubt extend through the far reaches of the universe as well as the depths of time.

It also seems to me that the natural processes for forming more complex structures from those basic building blocks were likely prevalent on the earth 4.5 billion years ago in a variety of forms, levels of completion and locations. We see that meteors bring not only pre-organic compounds (POCs), energy and rare nutrients, but compounds that can form cell like vesicles to concentrate the chemical interactions. Radioactivity may add energy to the equation, concentrating organic molecules, or deep earth thermal vents may be an additional source. 

We end with a scenario that has a random combination of plentiful and multitudinous POCs forming amino acids all over the earth, with membranous systems to contain and concentrate those molecules and their interactions within a protocell type capsule. We also see that random combination of plentiful and multitudinous amino acids into peptides and proteins is feasible, and that concentration and recombination within the membranous protocells enhances the probability that random combinations of them into the first "replicators" (the predecessors to RNA and DNA) is not as far fetched as it seemed at first. A simple building block process where the probability of a successful combination is almost inevitable: it is no longer a matter of "if" but of "when" it will occur under these conditions ... 

These "seeds of life" also existed in a world of constant motion, from the constant motion of sub-atomic particles to the interplay of atoms and molecules in chemical combinations, to the ebb and flow of various gases and liquids at different temperatures and densities, to the sometimes violent impact of meteors and eruptions. The existence of the first self-replicators would be little more than a slightly novel extension of this chemical existence, not much more remarkable than catalyzed reactions, their first "food" would have been the chemicals around them. 

Once a self-replicating chemical system occurs, however, the frequency and ability of it to reproduce will necessarily outpace the random chemical action from which it came, and the ones that are better able to adapt to and take advantage of the environment will outpace their competition ... they will evolve. From there it is but a small step to the first cell with the components and processes that we would classify as life. Life seems inevitable when given the conditions that existed for the beginning of life.

That is my take on the possibilities for the formation of life on earth.

Enjoy

Post Script

I am adding this to be perfectly clear on my intentions. For me the search for the elusive transition from non-life to life has to be two pronged:

(A) From the bottom up - looking for what happens naturally in a variety of environments to build more and more complex molecules from the materials available. This search also includes simulating a variety of early earth environments and possible environments on other planets (mars) or moons (europa). These molecules are the building blocks for the foundation, making towers by building onto them until the clouds are reached is the quest.

(B) From the top down - reducing life to a bare minimum, also in a variety of environments to find what can be done away with from the evolved systems and still have a (possibly crude and likely inefficient) forms of life. The variables will likely change with different environments and sources of energy that go with them. This is also where LUCA comes into the picture ("it is widely accepted that ... there was a period where RNA carried out the roles now performed by proteins and DNA"). Taking the skyscraping towers of today and deciphering the support structure, going back through time, paring it down to the bare minimums to find what the first original huts may have looked like.

This specific {topic thread} deals with (A), the bottom up approach, and involves known processes with known, verified results. A future essay may deal with (B), the top down approach, and how we got to RNA and DNA and other advanced molecules from previous stages. There is still a substantial gap between them, but as such research is done from both sides an awareness will build about how near one is to the other, very much like the way the (Golden Gate bridge was built from each side of the bay in closing increments (and even though most engineers of the day said it could not be done). It is also possible that future experiments based on the bottom up approach could result in a self-replicating proto-molecular system that fills some definitions of life without developing either RNA or DNA - presupposing either is similar to presupposing the hand of a designer.

I apologize for the length, but this is a compilation I have made over the last two to three years of points that to me constitute an overview of the state of current knowledge.

Thank you.

References:

(1) Brig Klyce (no date). Hoyle and Wickramasinghe's Analysis of Interstellar Dust. Cosmic Ancestry [Electronic version]. Retrieved 5Nov2005 from
http://www.panspermia.org/astronmy.htm

(2) (anon) (2004 Jun 22) Scientists discover two new interstellar molecules. Brightsurf Science News [Electronic version]. Retrieved 5Nov2005 from
http://www.brightsurf.com/news/june_04/NRAS_news_062204.php

(3) Jesse Bregman and Pasquale Temi (no date) Identifying Polycyclic aromatic hydrocarbon (PAH) molecules in Space. NASA Space Science and Astrobiology Division [Electronic version]. Retrieved 5Nov2005 from
http://spacescience.arc.nasa.gov/displaypage.cfm?page=Bregman&branch=ssa

(4) Gay Yee Hill (2005 Jul 28) Spitzer Finds Life Components in Young Universe. NASA News Archives [Electronic version]. Retrieved 5Nov2005 from
http://www.nasa.gov/vision/universe/starsgalaxies/spitzer-072805.html

(5) (anon) (2001 Oct 1) Scientists Toast the Discovery of Vinyl Alcohol in Interstellar Space. Spacedaily [Electronic version]. Retrieved 5Nov2005 from
http://www.spacedaily.com/news/life-01zi.html

(6) (anon) (no date) Rosalind Elsie Franklin (1920 - 1958). BBC Historical FIgures [Electronic version]. Retrieved 5Nov2005 from
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(7) Carolina Martinez (2005 Apr 25) Organic Materials Spotted High Above Titan's Surface. NASA News Archive [Electronic version]. Retrieved 5Nov2005 from
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(8) T. Encrenaz (1986) Search for organic molecules in the outer solar system. Adv Space Res. 1986;6(12):237-46. PMID: 11537827. PubMed abstract[Electronic version]. Retrieved 5Nov2005 from
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(9) S. Pizzarello, Y. Huang, L. Becker, R.J. Poreda, R. A. Nieman, G. Cooper, & M. Williams (2001 Sep 21) Organic Content of the Tagish Lake Meteorite. Science Vol 293 p2236-2239 [Electronic version]. Retrieved 5Nov2005 from
http://web99.arc.nasa.gov/PDF/tagish.pdf

(10) Catherine E. Watson (2002 Dec 11) Researchers Find Possible Precursors to Early Life on Earth in Meteorite. NASA News Archive [Electronic version]. Retrieved 5Nov2005 from
http://www.nasa.gov/centers/johnson/news/releases/2002/j02-122.html

(11) R. Koczor (2001 Dec 20) Sweet Meteorites. Science & NASA [Electronic version]. Retrieved 5Nov2005 from
http://science.nasa.gov/headlines/y2001/ast20dec_1.htm?list82388

(12) G. Cooper, N. Kimmich, W. Belisle, J. Sarinana, K. Brabham & L. Garrel (2001 Dec 20) Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth. Nature 414, p879 - 883 [Electronic version]. Retrieved 5Nov2005 from
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(13) F. Reddy (2004 Aug 26) Phosphorus from meteorites. Astronomy [Electronic version]. Retrieved 5Nov2005 from
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(14) W.K. Hartmann, G. Ryder, L. Dones, & D. Grinspoon (2000 Jul 18) The Time-Dependent Intense Bombardment of the Primordial Earth/Moon System. Origin of the Earth and Moon p493-512, University of Arizona Press, Robin M. Canup and Kevin Righter, eds. Excerpt [Electronic version]. Retrieved 5Nov2005 from
http://www.boulder.swri.edu/~luke/Papers/hartmann-etal-2000-lhb-review.pdf

(15) P Ehrenfreund, W Irvine, L Becker, J Blank, J R Brucato, L Colangeli, S Derenne, D Despois, A Dutrey, H Fraaije, A Lazcano, T Owen, F Robert and an International Space Science Institute ISSI-Team (2002 Oct 10) Astrophysical and astrochemical insights into the origin of life. Reports on Progress in Physics vol 65 p1427-1487 abstract [Electronic version]. Retrieved 5Nov2005 from
http://www.iop.org/EJ/abstract/0034-4885/65/10/202

(16) K. Burton (2002 Mar 27) NASA Scientists Create Amino Acids in Deep-Space-Like Environment. NASA News Archives [Electronic version]. Retrieved 5Nov2005 from
http://www.nasa.gov/centers/ames/news/releases/2002/02_33AR.html

(17) (anon) (2002 Mar 27) NASA Scientists Create Amino Acids in Deep-Space-Like Environment. NASA Astrobiology News Archives with links [Electronic version]. Retrieved 5Nov2005 from
http://astrobiology.arc.nasa.gov/news/expandnews.cfm?id=1319

(18) J.F. Kasting & A.A. Pavlov (2001 Jun 26) Archean Earth and Contemporary Life: The Transition from an Anaerobic to an Aerobic Marine Ecosystem (Sponsored by NASA Astrobiology Institute). Edinburgh International Conference Centre: Sidlaw [Electronic version]. Retrieved 5Nov2005 from
http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7607.htm

(19) S. Simpson (1999 Jan 9) Life's First Scalding Steps. Science News, Vol. 155, No. 2, p24 [Electronic version]. Retrieved 5Nov2005 from
http://www.sciencenews.org/pages/sn_arc99/1_9_99/bob1.htm

(20) S. Hart (2005 Oct 5) Hydrothermal Vents – Life’s First Home? NASA Astrobiology News Archives [Electronic version]. Retrieved 5Nov2005 from
http://nai.arc.nasa.gov/news_stories/news_detail.cfm?article=first_home.cfm

(21) S. Earle (2000 Aug) Origin of life in a hot iron-sulphur environment. Earth Science News [Electronic version]. Retrieved 5Nov2005 from
http://www.mala.bc.ca/~earles/pyruvate-aug00.htm

(22) J. Parnell (2003 Mar 20) Mineral Radioactivity Promotes Organic Complexity On Rocky Planets (#1119). Lunar and Planetary Science Conference XXXIV, Poster Session II [Electronic version]. Retrieved 5Nov2005 from
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1119.pdf

(23) L.J. Siegel (2005 Oct 5) Café Methane. NASA Astrobiology News Archives [Electronic version]. Retrieved 5Nov2005 from
http://nai.arc.nasa.gov/news_stories/news_detail.cfm?article=seeps.cfm

(24) T. Ferdelman, C. Borowski, N. Knab & H. Löbner (2005) Anaerobic methane oxidation in marine systems. Max Planck Institute for Marine Microbiology [Electronic version]. Retrieved 5Nov2005 from
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(25) C. Huber and G. Wächterhäuser (1998 Jul 31) Peptides by activation of amino acids with CO on (Ni,Fe)S surfaces: implications for the origin of life. Science 281(5377) p670-672 [Electronic version]. Retrieved 5Nov2005 from
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(26) S.A. Kauffman (1996 Aug 8) Self-Replication: Even peptides do it. Nature 382 [Electronic version]. Retrieved 5Nov2005 from
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(27) E.F. Mallove (1990 May 9) Self-Reproducing Molecules Reported by MIT Researchers. MIT Tech Talk [Electronic version]. Retrieved 5Nov2005 from
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(28) J. Sarfati (no date) Did scientists create life … or did the media create hype? Answers in Genesis article [Electronic version]. Retrieved 5Nov2005 from
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(29) J. Sarfati (2002 Dec 26) Self-replicating enzymes? Answers in Genesis TJ Archive Volume 11 Issue 1 [Electronic version]. Retrieved 5Nov2005 from
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(30) P. Ball (2004 Apr 26) Mineral brew grows 'cells'. Nature News archive [Electronic version]. Retrieved 5Nov2005 from
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(31) J.P. Dworkin, D.W. Deamer, S.A. Sandford, and L.J. Allamandola (2001 Jan 30) Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices. Proceedings of the National Academy of Science vol. 98 no. 3 p815-819 [Electronic version]. Retrieved 5Nov2005 from
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(32) C. Suh (2003 an 13) Researchers create novel life form. Science & Technology (no pub) United Press International [Electronic version]. Retrieved 5Nov2005 from
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(33) G. Rice, L. Tang, K. Stedman, F. Roberto, J. Spuhler, E. Gillitzer, J.E. Johnson, T. Douglas & M. Young (2004 May 18) The structure of a thermophilic archaeal virus shows a double-stranded DNA viral capsid type that spans all domains of life. Proceedings of the National Academy of Science vol. 101 no. 20 p7716-7720 [Electronic version]. Retrieved 5Nov2005 from
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Appendix A: Background Information from the references.

The purpose of this appendix is two-fold.

(1) Some articles are quite long and they often get into many other details, so the sections excerpted here are the pertinent ones to the essay above, and 

(2) Some articles are volatile on the web and may disappear or be edited or have the urls changed, so this allows the wording to be retained as captured on 5Nov2005.

Each entry is numbered to correspond to the references used above and a link to the article (as of 5Nov2005) is provided for ease of use. I have also made some parenthetical comments (not indented) at the ends of some entries.

A1 - Hoyle and Wickramasinghe's Analysis of Interstellar Dust
 http://www.panspermia.org/astronmy.htm

... Now, however, that organic polymers in space are abundant and may be necessary for life is well accepted. Today we often see stories about things like vinegar among the stars, or "buckyballs" from space as "the seeds of life". To that extent the scientific paradigm for the origin of life on Earth has already shifted.

But Hoyle and Wickramasinghe were not satisfied. In the middle 1970s, they turned their attention to an apparent anomaly in the spectrum. It had a low, broad "knee" centered at about 2.3 wavelengths per micrometer (the slight convexity on the slope at the left side of the graph). This spectral feature could be explained if the grains of dust were of a certain size, and hollow. After trying almost everything else first, in 1979, they looked at the spectrum for bacteria. Dried bacteria refract light as irregular hollow spheres, and their size range is appropriate. The match between the spectrum for dried bacteria (solid line) and the ones from the interstellar grains (dots, triangles and squares) was nearly perfect. Thinking without prejudice, Hoyle and Wickramasinghe concluded the grains probably were dried, frozen bacteria.

A2 - Scientists discover two new interstellar molecules
 http://www.brightsurf.com/news/june_04/NRAS_news_062204.php

A team of scientists using the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) has discovered two new molecules in an interstellar cloud near the center of the Milky Way Galaxy. This discovery is the GBT's first detection of new molecules, and is already helping astronomers better understand the complex processes by which large molecules form in space.

The 8-atom molecule propenal and the 10-atom molecule propanal were detected in a large cloud of gas and dust some 26,000 light-years away in an area known as Sagittarius B2. Such clouds, often many light-years across, are the raw material from which new stars are formed.

So far, about 130 different molecules have been discovered in interstellar clouds. Most of these molecules contain a small number of atoms, and only a few molecules with eight or more atoms have been found in interstellar clouds. Each time a new molecule is discovered, it helps to constrain the formation chemistry and the nature of interstellar dust grains, which are believed to be the formation sites of most complex interstellar molecules.

Starting with previously reported propynal (HC2CHO), propenal (CH2CHCHO) is formed by adding two hydrogen atoms. By the same process propanal (CH3CH2CHO) is formed from propenal.

After these molecules are formed on interstellar dust grains, they may be ejected as a diffuse gas. If enough molecules accumulate in the gas, they can be detected with a radio telescope. As the molecules rotate end-for-end, they change from one rotational energy state to another, emitting radio waves at precise frequencies. The "family" of radio frequencies emitted by a particular molecule forms a unique "fingerprint" that scientists can use to identify that molecule. The scientists identified the two new aldehydes by detecting a number of frequencies of radio emission in what is termed the K-band region (18 to 26 GHz) of the electromagnetic spectrum.

Complex molecules in space are of interest for many reasons, including their possible connection to the formation of biologically significant molecules on the early Earth. Complex molecules might have formed on the early Earth, or they might have first formed in interstellar clouds and been transported to the surface of the Earth.

A3 - Identifying Polycyclic aromatic hydrocarbon (PAH) molecules in Space
 http://spacescience.arc.nasa.gov/displaypage.cfm?page=Bregman&branch=ssa

Polycyclic aromatic hydrocarbon (PAH) molecules are the most abundant family of molecules in the interstellar medium after molecular hydrogen and carbon monoxide, and contain about 10% of all the interstellar carbon.

Recently, a spectral database has become available from the Infrared Space Observatory that contains objects in which we have found the C-H PAH stretch feature (near 3.26 µm) in absorption. Using the database of isolated neutral PAHs generated by the Ames Astrochemistry Laboratory, we can match the interstellar feature fairly well with a mixture of PAH molecules. However, the mixture is not unique and does not tell us which particular PAHs are present in space. This is demonstrated in the Figure which shows two fits to the absorption observed towards the protostellar source S140. The laboratory database contains only a few PAHs as large as those expected to survive the rigors of the interstellar medium, so it is perhaps not surprising that a precise match is still not possible. Techniques for obtaining lab spectra of larger PAHs exist, but making large PAHs for lab studies is very difficult. Once such lab data exist, being able to directly compare lab and interstellar spectra without using uncertain models could provide the first identification of individual PAHs in space.

A4 - Spitzer Finds Life Components in Young Universe
 http://www.nasa.gov/vision/universe/starsgalaxies/spitzer-072805.html

NASA's Spitzer Space Telescope has found the ingredients for life all the way back to a time when the universe was a mere youngster. 

Using Spitzer, scientists have detected organic molecules in galaxies when our universe was one-fourth of its current age of about 14 billion years. These large molecules, known as polycyclic aromatic hydrocarbons, are comprised of carbon and hydrogen. The molecules are considered to be among the building blocks of life.

"This is 10 billion years further back in time than we've seen them before," said Dr. Lin Yan of the Spitzer Science Center at the California Institute of Technology in Pasadena, Calif. Yan is lead author of a study to be published in the August 10 issue of the Astrophysical Journal. Previous missions - the Infrared Astronomical Satellite and the Infrared Space Observatory - detected these types of galaxies and molecules much closer to our own Milky Way galaxy. Spitzer's sensitivity is 100 times greater than these previous infrared telescope missions, enabling direct detection of organics so far away. 

Since Earth is approximately four-and-a-half billion years old, these organic materials existed in the universe well before our planet and solar system were formed and may have even been the seeds of our solar system. 

Spitzer's infrared spectrometer split the galaxies' infrared light into distinct features that revealed the presence of organic components. These organic features gave scientists a milepost to gauge the distance of these galaxies. This is the first time scientists have been able to measure a distance as great as 10-billion light years away using the spectral fingerprints of polycyclic aromatic hydrocarbons.

"These complex compounds tell us that by the time we see these galaxies, several generations of stars have already been formed," said Dr. George Helou of the Spitzer Science Center, a co-author of the study. "Planets and life had very early opportunities to emerge in the universe." 

A5 - Scientists Toast the Discovery of Vinyl Alcohol in Interstellar Space
 http://www.spacedaily.com/news/life-01zi.html

Astronomers using the National Science Foundation's 12 Meter Telescope at Kitt Peak, AZ, have discovered the complex organic molecule vinyl alcohol in an interstellar cloud of dust and gas near the center of the Milky Way Galaxy. The discovery of this long-sought compound could reveal tantalizing clues to the mysterious origin of complex organic molecules in space.
"The discovery of vinyl alcohol is significant," said Barry Turner, a scientist at the National Radio Astronomy Observatory (NRAO) in Charlottesville, Va., "because it gives us an important tool for understanding the formation of complex organic compounds in interstellar space.

The astronomers were able to detect the specific radio signature of vinyl alcohol during the observational period of May and June of 2001. Their results have been accepted for publication in the Astrophysical Journal Letters.

A6 - Rosalind Elsie Franklin (1920 - 1958)
 http://www.bbc.co.uk/history/historic_figures/franklin_rosalind_elsie.shtml

Franklin was an expert in using x-ray crystallography to study imperfectly crystalline matter, such as coal. She started work on the DNA by making very thin threads of it, bundling them and hitting them with a super-fine x-ray beam. She soon discovered the two forms of DNA. The easily photographed A form was dried, while the B form was wet. 

While much harder to photograph, her pictures of the B form showed a helix. Since the water would be attracted to the phosphates in the backbone, and the DNA was easily hydrated and dehydrated, she guessed that the backbone of the DNA was on the outside and the bases were therefore on the inside. This was a major step forward in the search for the structure of DNA.

In November 1951 Franklin presented her A and B form data to an audience that included James Watson, who was working in Cambridge with Francis Crick on the x-ray crystallography of protein. On hearing her lecture, the two men built their first model of DNA: a triple helix with the bases on the outside. However, in May 1952, Franklin got her first good photograph of the B form of DNA, showing a double helix. This was another major breakthrough. Franklin then continued working on the A form, having decided it would provide more data.

In early 1953, Watson and Crick saw some draft work by the American scientist Linus Pauling, and were given access to Franklin's data and her B form photographs showing DNA to be a multiple helix. From his work on proteins, Crick realised that her data implied an anti-parallel double helix. Franklin had reached this conclusion with regards to the A form, but had yet to apply this theory to the other form. 

Both projects were nearing the finish, but Franklin was pipped at the post. Franklin herself had written a draft paper on 17 March 1953, but was unable to publish before Watson and Crick, who were published the following day. Watson and Crick had broken a gentleman's agreement by working on DNA when they had claimed otherwise, and Franklin had offered valid criticism of their first model.

A7 - Organic Materials Spotted High Above Titan's Surface
 http://sse.jpl.nasa.gov/news/display.cfm?News_ID=10716

During its closest flyby of Saturn's moon Titan on April 16, the Cassini spacecraft came within 1,027 kilometers (638 miles) of the moon's surface and found that the outer layer of the thick, hazy atmosphere is brimming with complex hydrocarbons.

Scientists believe that Titan's atmosphere may be a laboratory for studying the organic chemistry that preceded life and provided the building blocks for life on Earth. The role of the upper atmosphere in this organic "factory" of hydrocarbons is very intriguing to scientists, especially given the large number of different hydrocarbons detected by Cassini during the flyby. 

... Complex mixtures of hydrocarbons and carbon-nitrogen compounds were seen throughout the range of masses measured by the Cassini ion and neutral mass spectrometer instrument.

"We are beginning to appreciate the role of the upper atmosphere in the complex carbon cycle that occurs on Titan," said Dr. Hunter Waite ...

Hydrocarbons containing as many as seven carbon atoms were observed, as well as nitrogen-containing hydrocarbons (nitriles). Titan's atmosphere is composed primarily of nitrogen, followed by methane, the simplest hydrocarbon. 

Interstellar clouds produce abundant quantities of organics, which are best viewed as the dust and grains incorporated in comets. This material may have been the source of early organic compounds on Earth from which life formed. Atmospheres of planets and their satellites in the outer solar system, while containing methane and molecular nitrogen, are largely devoid of oxygen. In this non-oxidizing environment under the action of ultraviolet light from the Sun or energetic particle radiation (from Saturn's magnetosphere in this case), these atmospheres can also produce large quantities of organics, and Titan is the prime example in our solar system. This same process is a possible pathway for formation of complex hydrocarbons on early Earth.

A8 - Search for organic molecules in the outer solar system.
 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract
&list_uids=11537827&query_hl=2

Recent developments of millimeter astronomy have led to the discovery of more and more complex molecules in the interstellar medium. In a similar way, attempts have been made to detect complex molecules in the atmospheres of the most primitive bodies of the Solar System, i.e. outer planets and comets, as well as in Titan's atmosphere. An important progress has been achieved thanks to the continuous development of infrared astronomy, from the ground and from space vehicles. In particular, an important contribution has come from the IRIS-Voyager infrared spectrometer with the detection of prebiotic molecules on Titan, and some complex organic molecules on Jupiter and Saturn. Another important result has been the observation of carbonaceous material in the immediate surroundings of Comet Halley's nucleus. In the near future, the search for organic molecules in the outer Solar System should benefit from the developments of large millimeter antennae, and in the next decade, from the operation of infrared Earth-orbiting spacecrafts (ISO, SIRTF) . 

A9 - Organic Content of the Tagish Lake Meteorite
 http://web99.arc.nasa.gov/PDF/tagish.pdf

The Tagish Lake meteorite fell last year on a frozen lake in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (~100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons. The insoluble carbon exhibits exclusive aromatic character, deuterium enrichment, and fullerenes containing "planetary" helium and argon. The findings provide insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites. 

A10 - Researchers Find Possible Precursors to Early Life on Earth in Meteorite
 http://www.nasa.gov/centers/johnson/news/releases/2002/j02-122.html 

The Tagish Lake meteorite fell to Earth over the Yukon Territory of Canada on Jan. 18, 2000. Parts of the meteorite were collected and kept frozen in an unprecedented level of cleanliness to ensure that it was not contaminated by any terrestrial sources.

Through extensive testing using, in part, electron microscopes, the researchers found numerous hollow, bubble-like hydrocarbon globules in the meteorite. They believe these organic globules, the first found in any natural sample, are very similar to those produced in laboratory simulations designed to recreate the initial conditions present when life first formed in the universe.

"While not of biological origin themselves, these globules would have served very well to protect and nurture primitive organisms on Earth," said Dr. Michael Zolensky, an author of the paper and a researcher in the Office of Astromaterials Research and Exploration Science at NASA's Johnson Space Center in Houston. "They would have been ready-made homes for early life forms."

Last year, researchers at NASA's Ames Research Center in Moffett Field, Calif., announced that they had made basically identical hydrocarbon globules in the laboratory from materials present in the early solar system and interstellar space.

"What we have now shown is that that these globules were in fact made naturally in the early solar system, and have been falling to Earth throughout time," Zolensky said.

A11 - Sweet Meteorites
 http://science.nasa.gov/headlines/y2001/ast20dec_1.htm?list82388

A NASA scientist has discovered sugar and several related organic compounds in two meteorites - providing the first evidence that another fundamental building block of life on Earth might have come from outer space.

Dr. George Cooper and co-workers from the NASA Ames Research Center found the sugary compounds in two carbon-rich (or "carbonaceous") meteorites. Previously, researchers had found inside meteorites other organic, carbon-based compounds that play major roles in life on Earth, such as amino acids and carboxylic acids, but no sugars.

"Finding these compounds greatly adds to our understanding of what organic materials could have been present on Earth before life began," Cooper said. "Sugar chemistry appears to be involved in life as far back as our records go." Recent research using ratios of carbon isotopes have pushed the origin of life on Earth to as far back as 3.8 billion years, he said. (An isotope is one of two or more atoms whose nuclei have the same number of protons but different numbers of neutrons.)

Scientists have long believed meteorites and comets played a role in the origin of life. Raining down on Earth during the heavy bombardment period some 3.8 billion to 4.5 billion years ago, they brought with them the materials that may have been critical for life, such as oxygen, sulfur, hydrogen and nitrogen. Sugars and the closely related compounds discovered by Cooper, collectively called "polyols," are critical to all known life forms. They act as components of the nucleic acids RNA and DNA, constituents of cell membranes and cellular energy sources.

A12 - Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth
 http://www.nature.com/nature/journal/v414/n6866/abs/414879a_fs.html

The much-studied Murchison meteorite is generally used as the standard reference for organic compounds in extraterrestrial material. Amino acids and other organic compounds important in contemporary biochemistry are thought to have been delivered to the early Earth by asteroids and comets, where they may have played a role in the origin of life. Polyhydroxylated compounds (polyols) such as sugars, sugar alcohols and sugar acids are vital to all known lifeforms—they are components of nucleic acids (RNA, DNA), cell membranes and also act as energy sources. But there has hitherto been no conclusive evidence for the existence of polyols in meteorites, leaving a gap in our understanding of the origins of biologically important organic compounds on Earth. Here we report that a variety of polyols are present in, and indigenous to, the Murchison and Murray meteorites in amounts comparable to amino acids. Analyses of water extracts indicate that extraterrestrial processes including photolysis and formaldehyde chemistry could account for the observed compounds. We conclude from this that polyols were present on the early Earth and therefore at least available for incorporation into the first forms of life.

A13 - Phosphorus from meteorites
 http://www.astronomy.com/asy/default.aspx?c=a&id=2423

Phosphorus plays a central role for life on Earth. It is an intimate part of life's architecture, contained in the salts that stiffen vertebrate bones and in phospholipids that form the walls of all living cells. It is linked to life's fundamental fuel, adenosine triphosphate (ATP), the energy storehouse that powers just about every physiological action. Even the lengthy genetic sequences of DNA and RNA — the blueprints for life itself — lie cradled within the twisting embrace of a pair of helical backbones built from phosphorus.

Yet for all its biological importance, the element is in remarkably short supply on Earth. According to recent studies, hydrogen atoms outnumber phosphorus atoms by 49 million to 1 in Earth's oceans, 2.8 million to 1 in the universe at large, and 203 to 1 in bacteria. Phosphorus fares a little better with oxygen atoms, which outnumber it by 25 million to 1 in the oceans, 1,400 to 1 in the cosmos, and 72 to 1 in bacteria. For every atom of phosphorus counted in such a census, carbon and nitrogen atoms appear, respectively, 974 and 633 times more often in the oceans, 680 and 230 times more frequently in the universe, and in numbers 116 and 15 times greater in bacteria.

Because phosphorus is much rarer in the environment than in life, understanding the behavior of phosphorus on the early Earth gives clues to life's orgin," said Matthew Pasek, a doctoral candidate at the University of Arizona's Lunar and Planetary Laboratory. Working with Dante Lauretta, assistant professor of planetary sciences at the university, Pasek argues that iron meteorites could have brought more phosphorus to Earth than occurs naturally. He presented his ideas at the 228th American Chemical Society national meeting in Philadelphia on Tuesday.

... Pasek and Lauretta began looking at meteorites as a possible source of the element. Meteorites contain several different phosphorus-bearing minerals, but the most important, said Pasek, is iron-nickel phosphide, also known as schreibersite. This metallic compound is extremely rare on Earth, but iron meteorites are peppered with schreibersite grains or even pinkish-colored veins of the mineral. Iron meteorites became the focus of the study because schreibersite is between 10 and 100 times more common in iron meteorites than other types.

Last April, Pasek, Lauretta, and undergraduate student Virginia Smith, mixed schriebersite with de-ionized water at room temperature. They then analyzed the liquid mixture using nuclear magnetic resonance. "We saw a whole slew of different phosphorus compounds being formed," Pasek said. "One of the most interesting ones we found was P2O7, one of the more biochemically useful forms of phosphate, similar to what's found in ATP." The analysis revealed numerous phosphate salts in different states of oxidation, Pasek told Astronomy.

A14 - The Time-Dependent Intense Bombardment of the Primordial Earth/Moon System
 http://www.boulder.swri.edu/~luke/Papers/hartmann-etal-2000-lhb-review.pdf

Because of several uncertainties and controversies about the conditions in the first few hundred million years, this review leads more toward continuing research problems than final solutions. On the one hand, direct cratering evidence indicates that the average cratering rate was higher at 4.0 Ga than it is today, and dynamical models suggest that this rate was still much higher before that. Planet accretion models suggest that the accretionary flux should have generally decreased rapidly in the first few hundred million years, with occasional short-lived spikes with a timescale on the order of 30 m.y. The half-life of planetesimal sweep-up is expected to have lengthened after planet formation at 4.55 Ga, possibly dovetailing with the declining rate picked up in the cratering record starting at about 4.0 or 3.9 Ga. On the other hand, several characteristics of the lunar petrologic record suggest a cataclysmic spike in cratering at 3.9–3.8 Ga, and even suggest, through lack of older impact melts, that the impact flux at 4.1–4.4 Ga was low instead of high. Many authors accept that four or more giant impact basins (requiring 102-km-scale impactors) formed within about 200 m.y. on the Moon; if this is accepted, it leads to interesting problems about the origin of the bolides and the kind of fragmentation event and/or parent bodies that could have produced such large impactors. Controversies still exist over whether the rock age distribution on the Moon can be explained by competition between destruction and production processes, or whether they require a cratering cataclysm at 3.9–3.8 Ga to destroy older rocks and create most of the known basins at that time. Solutions for these problems would have wide ramifications for the understanding of planetary accretion, lunar formation, and the environment in which crustal structure and biology originated on Earth. 

A15 - Astrophysical and astrochemical insights into the origin of life
 http://www.iop.org/EJ/abstract/0034-4885/65/10/202

Stellar nucleosynthesis of heavy elements such as carbon allowed the formation of organic molecules in space, which appear to be widespread in our Galaxy. The physical and chemical conditions—including density, temperature, ultraviolet (UV) radiation and energetic particles—determine reaction pathways and the complexity of organic molecules in different space environments. Dense interstellar clouds are the birth sites of stars of all masses and their planetary systems. During the protostellar collapse, interstellar organic molecules in gaseous and solid phases are integrated into protostellar disks from which planets and smaller solar system bodies form. After the formation of the planets 4.6 billion years ago, our solar system, including the Earth, was subjected to frequent impacts for several hundred million years. Life on Earth may have emerged during or shortly after this heavy bombardment phase, perhaps as early as 3.90–3.85 billion years ago, but the exact timing remains uncertain. A prebiotic reducing atmosphere, if present, predicts that building blocks of biopolymers—such as amino acids, sugars, purines and pyrimidines—would be formed in abundance. Recent modelling of the Earth's early atmosphere suggests, in contrast, more neutral conditions (e.g. H2O, N2, CO2), thus, precluding the formation of significant concentrations of prebiotic organic compounds. Moreover, even if the Earth's atmosphere were reducing, the presence of UV photons would readily destroy organic compounds unless they were quickly sequestered away in rocks or in the prebiotic ocean. Other possible sources of organic compounds would be high temperature vent chemistry, although the stability of such compounds (bases, amino acids) in these environments remains problematic. Finally, organic compounds may have been delivered to the Earth by asteroids, comets and smaller fragments, such as meteorites and interplanetary dust particles.

It is likely that a combination of these sources contributed to the building blocks of life on the early Earth. It may even have taken several starts before life surpassed the less than ideal conditions at the surface. What is certain is that once life emerged, it learned to adapt quickly taking advantage of every available refuge and energy source (e.g. photosynthesis and chemosynthesis), an attribute that eventually led to complex metabolic life and even our own existence.

A16 - NASA Scientists Create Amino Acids in Deep-Space-Like Environment
 http://www.nasa.gov/centers/ames/news/releases/2002/02_33AR.html

In a laboratory at NASA Ames Research Center in California's Silicon Valley, the team of astrobiologists shone ultraviolet light on deep-space-like "ices," simulating conditions that are commonplace in interstellar space. Deep-space ice is common water ice laced with simple molecules. The team subsequently discovered amino acids, molecules present in, and essential for, life on Earth.

The amino acids they detected (glycine, alanine and serine) are the basic parts of proteins from which all life is made. Proteins provide the structure for, and do all the work in, living things. 

"This finding suggests that Earth may have been seeded with amino acids from space in its earliest days," said Jason Dworkin of Ames and the SETI Institute. "And, since new stars and planets are formed within the same clouds in which new amino acids are being created, this increases the odds that life also evolved in places other than Earth."

A17 - NASA Scientists Create Amino Acids in Deep-Space-Like Environment
 http://astrobiology.arc.nasa.gov/news/expandnews.cfm?id=1319

A team of scientists at the NASA Astrochemistry Laboratory today announced that they had created amino acids in conditions mimicking deep space. Amino acids are the basic components of proteins, from which all life is made. According to researcher Max Bernstein, "We found that amino acids can be made in the dense interstellar clouds where planetary systems and stars are made. Our experiments suggest that amino acids should be everywhere, wherever there are stars and planets." 

The three amino acids produced in the Astrochemistry Lab are similar to those found previously in certain meteorites. Meteorites are pieces of asteroids or comets. The chemical similarities may indicate that amino acids were made in deep space, before the solar system formed, then eventually fell to Earth in meteorites. "This finding suggests that Earth may have been seeded with amino acids from space in its earliest days," said team member Jason Dworkin, adding, "[T]his increases the odds that life also evolved in places other than Earth." 

A18 - Archean Earth and Contemporary Life: The Transition from an Anaerobic to an Aerobic Marine Ecosystem
 http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7607.htm

Most (but not all) researchers accept that atmospheric O2 experienced a large increase near 2.3 Ga. Little agreement has been reached, however, concerning the nature of the atmosphere prior to that time. Evidence from uranium deposits and paleosols indicates that pO2 was less than ~10-3 PAL (times the Present Atmospheric Level) during the Archean, but theoretical considerations suggest that pO2 was actually much lower. As pointed out originally by J.C.G. Walker (Evolution of the Atmosphere, 1977), the initial rise of O2 should have occurred when the net source of O2 from photosynthesis followed by burial of organic carbon exceeded the volcanic outgassing rate of reduced gases. Photochemical models based on this presumption predict that pO2 would have been <10-7 PAL even in the presence of a significant photosynthetic O2 flux. Under these low-O2 conditions, CH4 produced by methanogenic bacteria could have reached ~1000 ppmv, or 600 times higher than today's value. At this concentration, CH4 would have made a significant contribution to the atmospheric greenhouse effect. Thus, the faint young Sun problem can be resolved without exceeding upper limits on atmospheric CO2 inferred from paleosols. Polymerization of this CH4 by UV photolysis may have produced hydrocarbon haze similar to that observed today on Saturn's moon, Titan. The haze could not have been too optically thick in the visible, however, or the surface would have been strongly cooled by the anti-greenhouse effect. Modeling suggests that UV shielding by the haze would have been minimal, so that early organisms would have had to contend with a nearly unattenuated solar UV flux. Accumulation of haze particles in sediments may account for the extremely 13C-depleted kerogens found in Late Archean sediments. Finally, evidence for mass-independent fractionation of sulfur isotopes provides strong support for a very low-O2 Archean atmosphere.

A19 - Life's First Scalding Steps 
 http://www.sciencenews.org/pages/sn_arc99/1_9_99/bob1.htm

The most detailed step-by-step blueprint for how Earth's oldest raw materials could have given rise to the stuff of life came out of the imagination of Günter Wächtershäuser, an organic chemist at the University of Regensberg in Germany. Ten years ago, Wächtershäuser conceived of an assembly-line process at the ocean floor that transforms basic inorganic chemicals into organic chains, the biological molecules that are the building blocks of life.

Wächtershäuser's factory enlists the elements of modern industry - all readily available at vents. The conveyor belt is the flat surface of metal sulfide minerals, such as iron pyrite, abundant in seafloor rocks. The raw materials are carbon- and hydrogen-rich gases from volcanic belches dissolved in the seawater. The workers that drive the assembly line - the keys to the whole process - are metallic ions in the sulfides.

In living cells, complex proteins called enzymes play the role of factory laborers, bringing certain molecules together and splitting others apart. Before enzymes appeared on the planet, Wächtershäuser says that metallic ions filled that catalytic role. Without these mediators, reactions might take months or years, or never happen at all, he adds. New components would never get added to the molecules passing by on the conveyor.

In Wächtershäuser's theory, the first organic molecule put together on the conveyor belt was acetic acid, a simple combination of carbon, hydrogen, and oxygen that is best known for giving vinegar its pungent odor. Formation of acetic acid is a primary step in metabolism, the series of chemical reactions that provides the energy that cells use to manufacture all the biological ingredients an organism needs.

Amino acids from a variety of sources almost certainly seasoned a broth on the planet's surface 4 billion years ago, Chyba says, but he points out that no one has ever satisfactorily explained how the widely distributed ingredients linked up into proteins. Presumed conditions of primordial Earth would have driven the amino acids toward lonely isolation. That's one of the strongest reasons that Wächtershäuser, Morowitz, and other hydrothermal vent theorists want to move the kitchen to the ocean floor. If the process starts down deep at discrete vents, they say, it can build amino acids - and link them up - right there.

Last year, Wächtershäuser and Huber did just that. They reported in the July 31, 1998 Science that at 100°C, they got amino acids to connect into short proteinlike chains called peptides.

A20 - Hydrothermal Vents - Life's First Home? 
 http://nai.arc.nasa.gov/news_stories/news_detail.cfm?article=first_home.cfm

... hydrothermal systems as the location for the emergence of life require no "special case" arguments. "They are probably one of the most common features throughout the entire history of the Earth," Shock says.

A few years ago Shock turned from theoretical work to field work at the hydrothermal systems in Yellowstone National Park. He hopes that by studying present-day hydrothermal life, he can determine what geochemical signatures to look for in the most ancient rocks.

Isua, on the on the edge of Greenland's ice cap, holds an outcrop of rock that appears to be 3.7 to 3.9 billion years old, only about half a billion years younger than the Earth itself.

After slicing the rocks with a diamond saw, Touret studied the slices using a specially fitted microscope. He saw tiny "bubbles" in the quartz crystals, and the bubbles, like minute glass globes, contained a fluid, Rollinson says.

"You see this half-filled inclusion, half water vapor, half liquid water, sort of wobbling under the effect of heating it up with the microscope lamp," Rollinson says.

Other researchers have studied tiny carbon grains embedded in different rocks found in the Isua formations. By measuring the ratio of carbon isotopes, these researchers determined that the grains contained carbon of biological origin. Two common and stable isotopes of carbon, carbon 12 and carbon 13, occur in a mixture in the Earth's atmosphere. Biological processes build organic molecules with a higher carbon 12:13 ratio than abiotic processes. And because both isotopes are stable, the ratio remains in all of life's products, even after billions of years.

Shock thinks these organisms may have left a detectable fossil record. But in this case, the fossils are chemical traces. "What are you going to look for? This is the question right now. By studying the active systems that are supporting hyperthermophiles [heat-loving organisms] you might have a better idea of what to go after in a fossil record that's hydrothermal.

A21 - Origin of life in a hot iron-sulphur environment
 http://www.mala.bc.ca/~earles/pyruvate-aug00.htm

German chemist Gunter Wachtershauser is a leader in the research on the hydrothermal origin of life, and has conducted numerous experiments which demonstrate how complex organic molecules can be formed from simple starting compounds - such as carbon monoxide (CO) - when metal sulphides are present as catalysts (Huber and Wachtershauser, 1997, Huber and Wachtershauser, 1998). It appears that the surfaces of metal sulphides can catalyze the binding of simple carbon molecules into new and more complex carbon molecules.

Researchers from the Carnegie Institution in Washington have recently taken this idea a step further by synthesizing the critical compound pyruvic acid (CH3-CO-COOH) from CO in the presence of iron-sulphide at 250° C and pressures equivalent to a depth of 7 km within the rock (Cody et al., 2000). They suggest that this process may have taken place at depth in the oceanic crust, and that the compounds formed could have been moved by groundwater to the upper crust, where the critical life-forming processes might have taken place at lower temperatures (100 to 150° C) and pressures.

The important components of this process are CO, Fe and/or Ni sulphides at high temperatures and pressures. All of these could have existed in proximity to volcanism in an early oceanic crust (Wachtershauser, 2000).

A22 - Mineral Radioactivity Promotes Organic Complexity On Rocky Planets
 http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1119.pdf

Radioelements were readily concentrated at the Earths surface during the Hadean and Archean. The oldest zircons indicate the production of granitic magma at 4.4Ga [3,4] (Fig. 1). Isotope data from these zircons indicate that there were surface waters at this time [3,4]. Zircons, monazites and other heavy minerals were liberated into surface sediments by erosion of plutonic hinterlands. Their high density means that the minerals are particularly susceptible to hydrodynamic sorting by moving water (rivers, tidal flow, wave action). The sorting of heavy minerals was enhanced by tidal motion induced by the presence of a moon, and they form concentrations in sediments throughout geological history. Hence, for example, they form accumulations at the margins of oceans, shallow seas and lakes. At the present planetary surface, radioactive monazite sands are concentrated at the margins of each of the large oceans, e.g. in Brazil, Vietnam, Australia, and India.

... The geological record includes widespread evidence for organic accretion and polymerisation around radioactive mineral grains (Fig. 2). In most cases this involved accretion of complex hydrocarbon fluids on grains in the sub-surface. The record includes accretions around uraninite grains in Archean sedimentary rocks, including substantial carbon deposition in the Witwatersrand uranium deposits [7], thorite and thoriferous monazite grains in Phanerozoic sandstones [8], and zircon grains in Precambrian gneisses. The oldest recorded accretions around uraninite are in the Swaziland Supergroup at ~3.3Ga (Fig. 1). Carbon coatings are also recorded around U-bearing apatite grains in early Archean >3.85Ga metasediments, Greenland [9], although an origin for these coatings by irradiation has not been assessed. Accretion of organic matter also occurs by mixing of organic-bearing and radioelement-bearing fluids, within hydrothermal systems or aquifers. Although these examples were accreted from complex molecules rather than simple compounds, they serve to show (i) that natural mineral grains have the potential to polymerize organic molecules and fix the products, and (ii) that this has been occurring on the Earth since Archean times. Polymerisation from methane rather than complex hydrocarbons may have produced carbonaceous accretions around uraninite in the Proterozoic of Canada and the Archean Witwatersrand deposits [10].

... The development of life is likely to have occurred in a setting where carbon-based molecules became concentrated, in addition to the requirements of liquid water and an energy source. The early Earth received a high flux of organic molecules from extraterrestrial sources that may have been photo-polymerized to a liquid organic layer at the oceanic surface [2]. Additionally methane from the mantle concentrated in hydrothermal systems may have contributed to the formation of hydrocarbon liquids or smogs in the atmosphere [12]. These concentrations of organic compounds at the surface could have been further processed by interaction with radioactive grains to yield increasingly complex molecules. Such interactions would have been more effective during permeation into the subsurface, as exposure of organics to grains at the sediment surface is transient, and coated grains are not seen on modern beaches. Nevertheless, such sands can induce short-term changes, as evidenced by increased chromosomal abnormalities in nearby human populations [13]. This effect is a consequence of emanated, dispersed radon, so an even briefer response time is expected for organic molecules in direct contact with the grains. Hence the irradiation mechanism could be effective in either of the ‘deep, dark’ or ‘surface, sunlit’ environments proposed for prebiotic chemistry.

A23 - Café Methane
 http://nai.arc.nasa.gov/news_stories/news_detail.cfm?article=seeps.cfm

Hydrothermal vents along the mid-ocean ridges have drawn much attention from scientists who study Earth's extreme environments - and what they may mean for the prospect of life elsewhere in the solar system.

But in recent years, researchers discovered life also thrives in other, much colder, lightless deep-sea ecosystems. Such habitats are created where faults in ancient sediments allow natural gas (methane) in deeply buried deposits to seep upward to the ocean floor to form methane ices known as gas hydrates.

These "methane seeps" are found all over the world on continental slopes some 500 to 1,000 meters (1,640 to 3,280 feet) beneath the waves. There, where pressures are 50 times greater than on Earth's surface, compressed natural gas becomes trapped in a lattice of water ice crystals to form gas hydrates at temperatures of 7 degrees Celsius (45 degrees Fahrenheit) or even warmer, depending on the crystal structure. The hydrates pile up in layers and mounds several meters (several yards) tall. 

... Without light for photosynthesis, bacteria and archaea engage in "chemosynthesis" near the Gulf of Mexico methane seeps and brine pools, converting methane and hydrogen sulfide into food that supports larger organisms.

... Until the discovery of undersea hydrothermal vents and methane seeps, "the deep ocean floor was seen as a desert," says Joye. "We now know there are oases on the seafloor where the diversity of life is similar to what we see on a salt marsh. Instead of being fueled by photosynthesis, these deep-sea ecosystems are fueled by chemosynthesis - the production of organic matter from inorganic oxidation."

A24 - Anaerobic methane oxidation in marine systems
 http://www.mpi-bremen.de/en/Anaerobic_methane_oxidation_in_marine_systems.html

The discovery of archaea-SRB aggregates involved in the anaerobic oxidation of methane in gas hydrate sediments was a major step forward in the understanding of this process and has shown the direction of future research. The biogeochemistry, molecular ecology and microbiology of anaerobic oxidation of methane and the microbial consortia involved is studied in different sediment systems. ... The studied systems include gas hydrates, cold seeps, mud volcanoes as well as the omnipresent sulfate-methane interface of shelf sediments. ... The goal is to understand the pathway of methane oxidation through the consortium and how the physiology and ecology of the involved microorganisms regulate the process. Experimental studies are done on sediments and enrichments to trace the fate of methane carbon and to analyze the environmental factors that determine the process rate. ... and the Genomics Program of the Department of Molecular Ecology aiming at the full genome sequencing of the ANME-1 and ANME-2 archaea, and the study of microbial processes of calcification in gassy sediments ....

(A picture shows aggregate of archaeen (red) and sulphate reducing bacteria (green) which are involved in the anaerobic oxidation of methane.)

A25 - C. Huber and G. Wächterhäuser, "Peptides by activation of amino acids with CO on (Ni,Fe)S surfaces: implications for the origin of life," 
 http://ecoserver.imbb.forth.gr/microbiology/s-e-papers/e-papers/peptideformationbyc_nifes.pdf

In experiments modeling volcanic or hydrothermal settings amino acids were converted into their peptides by use of coprecipitated (Ni,Fe)S and CO in conjunction with H2S (or CH3SH) as a catalyst and condensation agent at 100¡C and pH 7 to 10 under anaerobic, aqueous conditions. These results demonstrate that amino acids can be activated under geochemically relevant conditions. They support a thermophilic origin of life and an early appearance of peptides in the evolution of a primordial metabolism.

The activation of amino acids and the formation of peptides under primordial conditions is one of the great riddles of the origin of life. We have now found that under the hot, anaerobic, aqueous conditions of a setting with magmatic exhalations, amino acids are converted into peptides. Under these conditions we previously demonstrated the conversion of carbon monoxide into activated acetic acid in an aqueous slurry of coprecipitated (Ni,Fe)S at 100°C.

Peptides were formed from phenylalanine (F), tyrosine (Y), and glycine (G). In each run 500 mmol of the amino acid were reacted in a slurry of 1 mmol of FeS and 1 mmol of NiS in 10 ml of water with 4 mmol of CO gas (1 bar) in the presence of 500 mmol of hydrogen sulfide (H2S) or methanethiol (CH3SH) at 100°C and pH 7 to 10. In some of the runs 500 mmol of Na2HPO4 were added. After 1, 2, or 4 days, we determined the yield of the peptides and the pH in the water phase (2) (Table 1). No peptides were detectable, if under otherwise identical conditions CO was replaced by Ar, or if neither H2S nor CH3SH was added, or if both NiS and FeS were absent. In runs 13 and 14 and 19 to 22, about 3 nmol of tripeptides (Y-Y-Y) were detected after 1 and 4 days. 

A26 - Self-Replication: Even peptides do it By Stuart A. Kauffman
 http://www.santafe.edu/sfi/People/kauffman/sak-peptides.html

The authors show that a 32-amino-acid peptide, folded into an alpha-helix and having a structure based on a region of the yeast transcription factor GCN4, can autocatalyse its own synthesis by accelerating the amino-bond condensation of 15- and 17-amino-acid fragments in solution 
The design of this replicator was based on a protein found in nature, an alpha-helical coiled coil. Reasoning that a given alpha-helical subunit of the entire structure could be seen as a complementary binding surface, acting cooperatively to organize other participating peptide subunits in the coiling, the authors hoped that a similar 'template' function could be found in smaller fragments. The ligation, or joining, site was constructed so as to lie on the solvent-exposed surface of the alpha-helical structure of their 32-amino-acid sequence.

Do these results reflect a rare chemical quirk in the repertoire of peptides and polypeptides, or might they hint at a route to self-reproducing molecular systems on a basis for wider than Watson-Crick base-pairing in polynucleotides? At this stage, we cannot know, but the way is now open to investigate.

The new autocatalytic ligation-reaction system is merely exergonic: left to its own devices, the system will simply run to equilibrium. Can an autocatalytic system be created that carries out thermodynamic work cycles whereby the system sustains displacement from equilibrium, performs coordinated work and achieves such coordination by controlling, constraining and 'correcting' unwanted side reactions to enhance its own rate of reproduction?

The dominant view of life assumes that self-replication must be based on something akin to Watson-Crick base pairing. The 'RNA world' model of the origins of life conforms to this view. But years of careful effort to find an enzyme-free polynucleotide system able to undergo replication cycles by sequentially and correctly adding the proper nucleotide to the newly synthesized strand have not yet succeeded.

(While this does not show actual spontaneous self-replication in a natural environment, it does show that such systems can occur given the right conditions.)

A27 - Self-Reproducing Molecules Reported by MIT Researchers
 http://w3.mit.edu/newsoffice/tt/1990/may09/23124.html

Led by Professor Julius Rebek, Jr. of the Department of Chemistry, they have created an extraordinary self-replicating molecular system that they say might be regarded as a "primitive sign of life."

It is not life itself, of course, but it is a kind of molecular model of how self-replication - a most fundamental life process - can occur.

Amazingly, the laboratory-made molecule that Professor Rebek and his colleagues have created can reproduce itself without the "outside" assistance of enzymes. As such, and because of its specific constitution, the molecule embodies some of the "template" qualities of a nucleic acid, and some of the structural qualities of a protein.

Technically, the self-replicating compound made by the MIT group is called an amino adenosine triacid ester (AATE). This molecule was initially formed by reacting two other molecules.

The AATE replicates by attracting to one of its ends anester molecule, and to its other end an amino adenosine molecule. These molecules react to form another AATE. The "parent" and "child" AATE molecules then break apart and can go on to build still more AATE molecules. 

A28 - AIG: Did scientists create life ... or did the media create hype?
 http://www.answersingenesis.org/docs/3507.asp

... Upon reading the original scientific paper by the chemists involved, Claudia Huber and Günter Wächterhäuser, we find that all that was produced were a few building blocks joined in pairs (dipeptides) and a minuscule amount joined in threes (tripeptides). ....

(Note that they concede the peptides were created. Please note the blatant strawmen and the arguments by incredulity in the article as Sarfati dances around the issue trying to minimize the result.)

A29 - AIG: Self-replicating Enzymes?
 http://www.answersingenesis.org/tj/v11/i1/enzymes.asp

A group led by Julius Rebek synthesized a molecule called amino adenosine triacid ester (AATE), which itself consists of two components, pentafluorophenyl ester and amino adenosine. When AATE molecules are dissolved in chloroform with the two components, the AATE molecules act as templates for the two components to join up and form new AATE molecules. 

(Note again that they concede the AATE result. Again note the blatant strawmen and the arguments by incredulity in the article as Sarfati dances around the issue trying to minimize the result.)

A30 - Mineral brew grows 'cells' 
 http://www.nature.com/news/2004/040426/full/040426-5.html
(See abstracts at 
http://search.nature.com/search/?sp-q=Mineral+brew+grows+%27cells%27&sp-x-9=cat
&sp-q-9=NEWS&submit=go&sp-a=sp1001702d&sp-sfvl-field=subject%7Cujournal
&sp-t=results&sp-x-1=ujournal&sp-p-1=phrase&sp-p=all)

It is an experiment you could do in a school chemistry lab. But it produces weird growths that, although made purely from inorganic materials, share some of the characteristics of living organisms.

Maselko and Strizhak mixed calcium chloride, sodium carbonate, copper chloride, sodium iodide, hydrogen peroxide and starch. They found a fungus-like, soft membrane grows out of the mixture, enclosing a hollow cavity up to 1 cm across. Chemicals diffuse through this membrane, react inside the cavity, and then diffuse out, creating swirling clouds of violet liquid in the green base solution.

Rather than reaching equilibrium, this process persists. The reactions, say the researchers, are reminiscent of the way living cells sustain themselves, driven from equilibrium by the flow of chemicals and energy across their membranes.

Maselko and Strizhak even saw a kind of replication in their chemical brew. Sometimes the cell structures grew into forms with several lobes, or sprouted buds that split off from the parent membrane.

But although they look impressive, can these structures tell us anything about the origin of true life-forms? It seems the answer might be yes, because the differences between the two processes are not as fundamental as one might assume. 

Maselko is keen to follow up his discovery to see just how far the parallels with life run. "This is only the beginning," he says. "We will see many other systems like this. The next step will be to get these systems to evolve."

A31 - Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices.
 http://www.pnas.org/cgi/content/full/98/3/815

Infrared observations coupled with laboratory studies have shown that H2O, CH3OH, CO, CO2, and NH3 are major components of ices in molecular clouds (1-3). Energetic in situ processing of these interstellar ices into more complex species can be driven by cosmic ray-induced UV in dense clouds (4), the significantly enhanced UV field in star-forming regions, and high energy particle bombardment and UV radiation from the T-Tauri phase in stellar birth (5). Laboratory studies have shown that such energetic processing produces many new organic compounds in these ices, including species far more complex than the starting materials (6-8). Given that this processing occurs wherever new stars are being created and that there is isotopic evidence from meteorites and cosmic dust that these materials can survive incorporation into forming stellar systems and subsequent delivery to planetary surfaces (9), this photochemical processing could potentially play a significant role in prebiotic chemistry.

The starting gas-mixture (H2O:CH3OH:NH3:CO = 100:50:1:1) was chosen as a simple mixture that reflects the composition and concentrations of the major interstellar ice components (1, 6, 14). Different concentrations of the same mixture (all H2O-rich) have also been studied and produce analogous results. This mixture was deposited onto a 15 K substrate and irradiated with vacuum UV to simulate the processing of icy grains in dense molecular clouds. When the ice was warmed to room temperature, there is an oily organic residue which remains (6). This material was extracted, dried, and analyzed in aqueous media via microscopy. We found that some components of the photochemical product produced water-insoluble fluorescent droplets under these conditions. Fig. 1A shows the droplets by phase microscopy, and Fig. 1B shows the emission at 450-520 nm when excited at 400-430 nm. The droplets are roughly 10-50 µm in diameter and have apparent internal structures on a 1-µm scale, which are presumably related to phase separations that occur within the organic components of the droplets.

To determine whether the amphiphilic components of the droplets can assemble into membranous vesicles having interior spaces, we encapsulated a polar dye via a cycle of wetting and drying. This wetting-drying cycle has been proposed as a probable mechanism by which relatively impermeant molecules could be captured by membranes in the prebiotic environment (15). We found that substantial numbers of highly fluorescent vesicles were present, most in the range of 1-10 µm (Fig. 5 Middle and Bottom), but some are considerably larger (Fig. 5 Top). True encapsulation of the dye was demonstrated by addition of 5 mM Triton X-100, a nonionic detergent that is known to permeabilize lipid bilayers (16). The detergent was introduced at one edge of the microscope slide, and, as it slowly spread under the coverslip, the vesicles became nonfluorescent, indicating that pyranine was released and diluted in the surrounding medium through defects induced in the membranes by the Triton X-100. This release confirms that the dye was trapped inside the vesicles, rather than merely dissolved within their membranes.

We also compared the behavior of the laboratory-produced residue with the extraterrestrial organic material extracted from a carbonaceous meteorite. Although the Murchison meteorite has a complex history and was derived from a more complex mixture than the residue in our simulations, Fig. 6 shows that strikingly similar vesicular structures self-assemble from chloroform-methanol extracts of the Murchison meteorite sample when a phosphate buffer is added to the organic extract. It is also interesting to note that, like the droplets found in extracts of the Murchison meteorite, the residue droplets show an increased granular or foamy texture during UV (but not visible light) exposure in the microscope, as evident in the larger droplets in Figs. 1 and 3. The physical changes in the droplets on illumination indicate that UV-driven photochemical reactions can occur in the organic compounds that compose the droplets. The nature of this photochemistry may have prebiotic significance, in that pigments present in the mixture are apparently able to capture UV light energy and use it to produce increasingly complex structures in the droplets.

A32- Researchers create novel life form
 http://www.upi.com/inc/view.php?StoryID=20030113-061458-1878r

Researchers said Monday they have manipulated an organism successfully to make it produce an unnatural amino acid in addition to its natural counterparts.

"It's a bona fide unnatural organism now," said lead researcher Ryan Mehl, previously at Scripps Research Institute where the study was conducted and currently an assistant professor of chemistry at Franklin and Marshall College in Lancaster, Pa.

The Scripps researchers used a strain of the common bacterium Escherichia coli and replaced a chunk of its genetic code called a stop codon - whose function is to halt protein-making machinery - with a code for the unnatural amino acid, p-aminophenylalanine, or pAF.

As is common practice with scientists manipulating bacteria, the study's authors also altered the E. coli so it would not survive outside of the laboratory.

A33 - The structure of a thermophilic archaeal virus shows a double-stranded DNA viral capsid type that spans all domains of life
 http://www.pnas.org/cgi/content/full/101/20/7716?maxtoshow=&HITS=10&hits=10
&RESULTFORMAT=&fulltext=%22George+Rice%22&searchid=1131258210503_5791
&stored_search=&FIRSTINDEX=0&journalcode=pnas

Of the three domains of life (Eukarya, Bacteria, and Archaea), the least understood is Archaea and its associated viruses. Many Archaea are extremophiles, with species that are capable of growth at some of the highest temperatures and extremes of pH of all known organisms. Phylogenetic rRNA-encoding DNA analysis places many of the hyperthermophilic Archaea (species with an optimum growth 80°C) at the base of the universal tree of life, suggesting that thermophiles were among the first forms of life on earth. Very few viruses have been identified from Archaea as compared to Bacteria and Eukarya. We report here the structure of a hyperthermophilic virus isolated from an archaeal host found in hot springs in Yellowstone National Park. The sequence of the circular double-stranded DNA viral genome shows that it shares little similarity to other known genes in viruses or other organisms. By comparing the tertiary and quaternary structures of the coat protein of this virus with those of a bacterial and an animal virus, we find conformational relationships among all three, suggesting that some viruses may have a common ancestor that precedes the division into three domains of life >3 billion years ago

The lack of genomic similarity of these viruses creates the need to look at other similarities between these viruses to infer relationships. An alternative approach of comparison among long-separated viral lineages is the possibility that they share a common innate "self," which is based on the structural and assembly principles of the virion. The proposal that molecular organization (folding) of biological macromolecules preceded the appearance of early life forms suggests there may be a conservation of structure (and function) that may be useful for penetrating deep into the history of life (32). The similar organization of the capsid proteins from the bacteriophage PRD1, the eukaryotic adenovirus, and now the archaeal STIV suggests long-range evolutionary relationships among these viruses from all three domains of life. 

There are other potential explanations for this astounding similarity. First, there could have been massively convergent evolution (although this is unlikely), because there are many different virus morphologies that can infect Archaea, Eukarya, and Bacteria. A second explanation is that there was horizontal gene transfer among all three domains, a possibility that cannot be ruled out but is also unprecedented and must have happened long ago for all sequence resemblance to have disappeared. Finally, a common ancestor responsible for the innate self still evident in STIV, PRD1, PBCV-1, and adenovirus is postulated that would have preceded the divergence of the three domains of life >3 billion years ago. The striking similarity in the characteristics of these three major virion proteins of these viruses strongly suggests the latter. 

(There is some question about whether viruses qualify as forms of life, and this usually hinges on whether viruses can replicate themselves on their own in a natural environment. The environment in question would not be like the one we live in to day, as there is very strong evidence that the oxygen in the atmosphere is a result of life after it evolved. The logical conclusion is that the first forms of life would be different from later forms of life, and very possibly quite different.

This is not to claim that the first life form was a virus so much as a question, whether viruses are remnants of that first form of life, a shell of their former existence, a clue.)

EOF.

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(Note: this is an essay and as such represents the opinions of the author. You can e-mail comments to me at RAZD8@yahoo.com)

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