Biocosmology: Cosmic Symmetry-Breaking and Molecular Evolution
We now explore the structural relationship between cosmological symmetry-breaking and the form of molecular evolution leading to biological systems on Earth. It thus forms an alternative to historical hypotheses in which the form of biogenesis is believed to be the product of a linked sequence of specific conditions, bridged by stochastic selection processes.
1 : A MOLECULAR BIOLOGICAL VIEW OF COSMIC SYMMETRY-BREAKING.
The rich diversity of structure in molecular systems is made possible by the profound asymmetries between the nuclear forces and electromagnetism. Although molecular dynamics is founded on electromagnetic orbitals, the diversity of the elements and their asymmetric charge structure, with electrons captured by a spectrum of positively charged nuclei, is made possible through the divergence of symmetry of the four fundamental forces. The non-linear electromagnetic charge interactions of these asymmetric structures is responsible for both chemical bonding and the hierarchy of weak bonding interactions which result in the non-periodic secondary and tertiary structures of proteins and nucleic acids. It also provides the basis for a bifurcation theory which could give biogenesis the same generality that nucleogenesis has.
Differentiation and Inflation: The Microscopic and Cosmic Scales
Force Differentiation: The strong (nuclear binding) and weak (neutron decay) forces, electromagnetism and gravity are believed to have emerged from a single superforce shortly after the big bang, fig1(a). The strong force is believed to be a secondary effect of the colour force in much the same way that molecular bonding is a secondary consequence of the formation of atoms. The weak force has become short range because it is mediated by massive particles, which are believed to gain an extra degree of freedom by assimilating a Higg's boson (Georgi 1981, t'Hooft 1980, Veltman 1986). The symmetry between the Z and W particles of the weak force and the massless photon of elecromagnetism is thus broken by the lower energy of the polarized configuration, fig 1(b). Even heavier particles are believed to separate the strong force from these two. Force reconvergence occurs at the unification temperature fig 1(c). The strong force mesons gain mass from a different mechanism, being the energies of the bound states of the colour force, whose gluons are massless, but confined. The separation of gravity from the other forces is more fundamental because it involves the structure of space-time and may be described by a higher-dimensional superstring force in which particles become excited loops or strings in a higher dimensional space-time which is compactified into our 4-dimensional form (Green 1985, 1986, Goldman et.al. 1988, Freedman & van Nieuwenhuizen 1985).
Cosmic Inflation: A universe in a symmetrical state, but below its unification temperature is in an unstable high-energy false vacuum. The energy of the Higg's field causes inflation, in which the universe has net gravitational repulsion and expands exponentially, smoothing irregularities to fractal structures on the scale of galaxies (Guth & Steinhardt 1984). The breakdown of the false vacuum then releases a stream of high-energy particles as latent heat, to form the hot expanding universe under attractive gravitation. The gravitational potential energy thus gained equals that of the energetic particles, making the generation of the universe possible from a quantum fluctuation. However variations in the cosmic background radiation are consistent with a big-bang smoothed by inflation (Smoot 1992).
Interactive Dynamics:
The interaction between the resulting wave-particles also results in distinct effects on the microscopic and cosmic scales, namely galaxy and star formation and genesis of nuclei, chemical elements, and finally molecules, in which the non-linear nature of chemical bonding becomes fully expressed in complex tertiary structures. These interactions are modified indirectly by the nuclear forces which contribute asymmetries, spin-effects, weak decay and the nuclear energy of stars.
Particle Interaction-1: Nucleosynthesis as a Cosmological Dynamical System. The nucleosynthesis pathway generates over 100 atomic nuclei from the already composite proton and neutron. Parity between protons and neutrons is slightly broken via weak decay, fig 1(e) to balance between the lowest nuclear quantum states being filled and increasing electromagnetic repulsion. The process is exothermic and moderated by the catalytic action of several of the isotopes of lighter elements such as carbon and oxygen. The cosmic abundance of the elements fig1(d) reflects the binding energies of the nuclei and stable a-particle-like shells (Moeller et. al. 1984). The nucleosynthesis pathway has a cosmologically-general form despite having some variation in individual star systems.
Particle Interaction-2: Moleculosynthesis. The Culminating Dynamic Although, by comparison with the energies of cosmic creation or even astronomical bodies, the structures of biomolecules seem much too fragile to be a cosmological feature, symmetry-breaking of the forces leads inevitably to molecular structures as a hierarchical culmination of the interactive phase. Quarks are bound by gluons into composite particles such as the proton p+ and neutron n. These interact by the strong force via the nucleosynthesis pathway to form the elementary nuclei. Subsequently the weaker electromagnetic force interacts, also in two phases, firstly by the formation of atoms around nuclei and then by secondary interaction to form molecules. The latter phase occurs in a sequence of stages through successive strong and weak bonding interactions, producing the complex tertiary structures of biomolecules, fig 1(f,g).
The Cosmic Interaction Sequence: The Pathway to the Planetary Biosphere Galaxy formation is followed by the generation of the chemical nuclei in the supernova explosion of a short-lived hot star. In the second phase these elements are drawn into a lower energy long-lived sun-like star, the lighter [bio]elements, occurring in high cosmic abundance as a result of nucelosynthesis dynamics, fig1(d), becoming concentrated on mid-range planets. The final re-entry of the forces is thus represented by stellar photon irradiation of molecular systems, under gravitational stabilization on a planetary surface.
THE NON-LINEAR DYNAMICS OF QUANTUM CHEMISTRY
A Brief Survey of Non-linear Orbital Theory
The fact that the laws of chemistry were discovered sooner and were relatively easier to explore than the conditions underlying the unification of electromagnetism with the nuclear forces has resulted in an anomalous historical perspective which has helped to obscure some of the most interesting and complex manifestations of chemistry as a final interactive consequence of cosmological quantum symmetry-breaking. The increasing nuclear charge permits an unparalleled richness and complexity of quantum bonding structures in which electron-electron repulsions, spin-obit coupling, and other effects perturb the periodicity of orbital properties and lead to the development of higher-order molecular structures.
Although quanta obey linear wave amplitude superposition, chemistry inherits non-linearity in the form of the attractive and repulsive charge interactions between orbital systems. Such non-linear interaction, combined with Pauli exclusion, is responsible for the diversity of chemical interaction from the covalent bond to the secondary and tertiary effects manifest in the complex structures of proteins and nucleic acids.
The source of this non-linear interaction is the foundation of all chemical bonding, the electric potential. Although the state vector of a quantum-mechanical system comprises a linear combination of eigenfunctions, the electrostatic charge of the electron causes orbital interaction to have non-linear energetics.

Quantum matrix methods are generally simplified to take account of only one aspect of molecular interaction and involve extensive approximations such as the independent particle approximation and Hükel theory (Brown 1972). The non-linear interactions of electron repulsions and spin-orbit coupling in the global context of molecular tertiary structure require complex computer techniques for example to predict the 3-D structure of protein molecules. These are only beginning to simulate the folding of complex molecules, again requiring approximation techniques.
The capacity of orbitals, including unoccupied orbitals, to cause successive perturbations of bonding energetics results in an interaction succession from strong covalent and ionic bond types [200-800 kj/mole] through to their residual effects in the variety of weaker H-bonding, polar, hydrophobic, and van der Waals interactions [4-40 kj/mole] merging into the average kinetic energies at biological temperatures [2.6 kj/mole at 25oC], (Watson et. al. 1988). These are responsible for secondary structures such as the a-helix of proteins and base-pairing and stacking of nucleic acids, and result in the tertiary effects central to enzyme action, whose energetics are determined by global interactions in complex molecules.

The cooperative reactivity of the active site of hexokinase demonstrates how, even after resolving the covalent and successive weaker bonding effects, and the local interactions of individual sides chains, and the larger fractal structures arising from weak bonds forming secondayry and tertiary protein structure, the entire enzyme is still capable of marked global conformation changes of a highly energetic nature. Chemical forces are thus fractal, leading right up to the globally fractal tissue structures we see in organismic biology, from the lungs to the brain. This is confirmed in the fractal dynamics of key cell structures (Watson et. al.).

Beloushov-Zhabotinskii type reaction giving rise to three-dimensional scroll waves (CK).

2.2 Fractal and Chaotic Dynamics and Structure in Molecular Systems.
Most minerals adopt periodic crystal geometries. Although some anomalies are disordered, many such as those superconducting perovskites have higher-order geometrical regularity. By contrast, the irregularties in polymers such as polypeptides and RNA is critical are establishing the richness of their tertiary structures, and their bio-activity. Variable sequence polymers with significant tertiary structure are non-periodic because the unlimited variety of monomeric primary sequences induce irregular secondary and tertiary structures. These irregularities are central to biochemistry because they result in powerful catalysts which can alter the reaction dynamics because of the generation of local activating sites globally potentiated through intermolecular weak-bonding associations. They also permit allosteric regulation. Despite being genetically coded, such molecules form fractal structures both in stereochemical terms and in terms of their relaxation dynamics.
Prigogine's theory of non-equilibrium thermodynamics, in which maximum entropy is replaced by a more general critical point of entropy production, which in an open system may not be a maximum. The associated oscillating chemical systems such as the Beloushov-Zhabotinskii reaction have demonstrated the capacity of chemical systems to enter into non-linear concentration dynamics, including limit cycle bifurcations. Period-doubling bifurcations and chaotic concentration dynamics have also been observed . Similar dynamics occur in electrochemical membrane excitation. The living cell is a non-equilibrium open thermodynamic system whose boundary, the memerane, exchanges material with the outside world. This makes it possible for life to be a negentropic system within a universe where entropy is increasing. The photosynthetic conversion of light to chemical energy and structural growth in our great forests is a prime example.
By contrast, viruses do not form a thermodynamic system as such, but rather a system of pure information. The first emergence of polynucleotides may similarly have been associated with the acrual of such information by a more direct negentropic route, phase transition.

 

Fig 2: (a) Symmetry-breaking model of selection of bioelements, as an interference interaction between H and CNO, followed by secondary ionic, covalent and catalytic interactions. (b) Boiling points of hydrides illustrate the optimality of H2O as polar H-bonding and structural medium for biological structure (CK). 3-D periodic table Sci Am. Sep 98
Biogenesis as a Central Synthetic Pathway
One of the central ideas of the cosmological biogenesis model is that the molecular interactions forming the pathways to the origins of life as we know it are not just an accidental set of chemical reactions out of a great variety of ad-hoc initial conditions, but that they represent a fundamental biforcation arising ultimately from cosmological symmetry-breaking of the four forces. The non-linear properties of electron orbitals cause the periodic table to have a critical sequence of bifurcations relating to the fundamental interactions.
Traditionally chemists have become so wedded to the idea of atoms and molecules as simply the "building blocks of the universe", as Isaac Asimov once put it that they cannot comprehend how they might interact as a quantum dynamical system. The fact that chemical bonding is possible between a large variety of atoms in some form or other leads to the loss of an understanding for how the non-linear electronic interactions gave rise to chemical bonding in the first place. It also leads to a mechanistic view of biogenesis, in which there is no underlying dynamical theory, but simply a search for the underlying special or initial conditions which caused the first self-replicating reaction to get going. The aim is thus either to set up a laboratory reaction by placing extreme order on the system, to elucidate this reaction pathway, or an attempt to use random processes and probabilistc arguments to model the likelihood that some collection of replicating molecules might accidentally come together. This has marred prebiotic research and profoundly slowed its advances.
Two illustrations hightlight this conceptual barrier. There is a 40 year time span between Miller and Urey's first spark experiments elucidating pathways from simple precursors to the purine nucleic acid bases, and the modification of this synthesis which led to good yields of the pyrimidines. Likewise there has been two decades of research in attempting to polymerize ribonucleotides, littered with failures due to oversimiplification of RNA interactions and mechanistic variants such as peptide-nucleic acids, before the ribonucleotide evolution techniques of Szostak and finally simple relationship between polymerizing ribonucleotides and montmorrilonite clays became obvious.

The cosmological biogenesis theory asserts the following three points:
1. All molecular interaction is highly non-linear, and forms an unresolved fractal interactive milieu which permits not only the cascade of weaking bonding and global interactions characterizing protein enzymes and nucleic acids but also on a larger scale the tissue structures of whole organisms. This means that, while nature can be crystalline, it can also display emergent properties on larger scales which are very difficult to predict from an examination of the components "the whole is more than the sum of the parts". The non-linear perspective realizes emergence within an in-principle reductionist viewpoint because the underlying principles are quantum chemistry, but the consequences are emergent fractal interaction. This situation is clearly illustrated in the great difficulty of fully accurate modelling of the electronic dynamics of even simple atoms because they are many-body problems, and by the complexity of the protein-folding problem (Sci Am. Jan 91 see also Shape is All NS 24 Oct 98 42).
2. The entire molecular environment is non-linear in a way which is capable of exploring its phase space in the manner of a chaotic dynamical system. This means that planetary, terrestrial and molecular systems display sufficient chaos to generate all the varieties of structural interaction possible. These non-linearities make the natural environment a quantum equivalent of a Mandelbrot set in which a potentially infinite variety of dynamics are possible. The overwhelming majority of chemical experiments into the origins of life (with the notable exception of the original spark experiments) attempt to defeat this process by introducing simple overweaning conditions of order to force simple clear-cut products out of the system.
3. Underlying this rich chaotic interaction is a universal bifurcation pathway which is a direct consequence of the form of cosmological symmetry-breaking of the four quantum forces. While there may be more than one way that molecular replication could occur in chemistry, the RNA-based form of life is nevertheless a central bifurcation product of the interaction between the fundamental forces and by no means a mere accident of unlikely circumstances.

Principal Symmetry-splitting : The Covalent Interaction of H with C, N, O.
Quantum interference interaction between the two-electron 1s orbital and the eight-electron 2sp3 hybrid. The resulting three dimensional covalent bonds give C, N and O optimal capacity to form diverse polymeric structures in association with H. Symmetry is split, because the 1s has only one binding electron state, while the 2sp3 has a series from with differing energies and varied occupancy, as the nuclear charge increases. The 1s orbital is unique in the generation of the hydrogen bond through the capacity of the bare proton to interact with a lone pair orbital. The CNO group all possess the same tetrahedral sp3 bonding geometry and form a graded sequence in electronegativity, with one and two lone pairs appearing successively in N and O.
Polymeric condensation of unstable high-energy multiple-bonded forms. Some of the strongest covalent bonds are the multiple-bonds such as - CC -, - CN, and > C = O. These can be generated by applying any one of several high-energy sources such as u.v. light, high temperatures (900oC), or spark discharge. Because of the higher energy of the resulting pi-orbitals, these bonds possess a specific type of structural instability in which one or two pi-bonds can open to form polymeric structures, particularly when bound to H and alkyl groups, as under reducing conditions. Most of the prebiotic molecular complexity generated by such energy sources can be derived from mutual polymerizations of HCCH, HCN, and H2C = O, including purines, pyrimidines, key sugar types, amino acids, porphyrins etc. They form a core pathway from high energy stability to structurally unstable polymerization, which we will examine in the next section.
Radio-telescope data demonstrates clouds of HCN and H2CO spanning the region in the Orion nebula where several new stars are forming. All of A, U, G, and C have been detected in carbonaceous chondrite meteorites, which also contain membrane-forming products. HCN and HCHO polymerizations also lead to membranous microcellular structures. Although the presence of CO2 as a principal atmospheric gas on the early earth could have reduced the quantities of such reduced molecules, HCN could have been produced as a transient in the early atmosphere leading to heterocyclic products. A variety of microenvironments would still have had access to reducing conditions.
The formation of conjugated double and single bonds in these reactions results is the appearance of delocalized pi-orbitals. Such orbitals in heterocyclic (N, C) rings with conjugated resonance configurations also enable lone pair n > p* and also p > p* transitions, resulting in increased photon absorption. These effects in combination play a key role in many biological processes including photosynthesis, electron transport and bioluminescence.

Secondary Splitting between C, N, and O : Electronegativity Bifurcation.
In addition to varying covalent valencies, lone pairs etc., the 8-electron 2sp3 hybrid generates a sequence of elements with increasing electronegativity, arising from the increasing nuclear charge. This results in a variety of secondary effects in addition to the oxidation-reduction parameter, from the polarity bifurcation into aqueous and hydrophobic phases to the complementation of CO2 and NH3 as organic acid and base.

Optimality of H2O: Polarity, Phase and Acid-base bifurcations. Ionic and Hydrogen bonding.
Outside metals such as mercury, water has one of the highest specific heats. This is a reflection of the large number of conformational degress of freedom it contains. It is also capable of a very unusual number of interactions, ionic, polar, H-bonding, acid-base and the polarity bifurcation into hydrophilic (water-loving) and hydrophobic (oily) phases in biological molecules and structures such as the lipid membrane, which is a sandwich of oily and watery moieties.

Dehydration is the common currency of polymerization, beginning with the mineral pyrophosphate linkage of ATP. The central biopolymers, polynucleotides, polypeptides and polysacharides are uniformly linked by the removal of a molecule of water, dehydration in the aqueous medium. Furthermore the three-dimensional structures of the nucleic acid double-helix, globular enzymes, membranes and ion channels are all made structurally and energetically possible only through the interactions of these molecules with water and the induced H2O structures that form around them in solution. Both nucleic acids and proteins consist of a balance of hydrophilic and hydrophobic interactions which in the former give hydrophobic base-stacking within a polar back-bone and with enzymes a non-polar micelle surrounded by hydrophilic groups.
Differential electronegativity results in several coincident bifurcations associated with water structure. A symmetry-breaking occurs between the relatively non-polar C-H bond and the increasingly polar N-H and O-H. This results in phase bifurcation of the aqueous medium into polar and non-polar phases in association with low-entropy water bonding structures induced around non-polar molecules. This is directly responsible for the development a variety of structures from the membrane in the context of lipid molecules, to the globular enzyme form and base-stacking of nucleic acids.
The optimal nature of water as a hydride is illustrated in boiling points. By comparison with ammonia H3N, water H2O has balanced doning and accepting H-bonds and a stronger polarity. Such polar properties are also clearly optimal over H2S, alcohols etc.
The discovery by the ISO Infra-red Space Observatory, of widespread incidence of water around stars, planets and throughout the universe where stars are forming has led increasing weight tothe cosmological status of water as a pre-cursor to life. - AP Apr 98
Water provides several other secondary bifurcations besides polarity. The dissociation of H2O  into H+ and OH- lays the foundation for the acid-base bifurcation, while ionic solubility generates anion-cation. H-bonding structures are also pivotal in determining the form of polymers including the alpha helix, base pairing and solubility of molecules such as sugars. Many properties of proteins and nucleic acids, are derived from water bonding structures in which a mix of H-bonding and phase bifurcation effects occur. The large diversity of quantum modes in water is exemplified by its high specific heat contrasting with that of proteins (Cochran 1971). Polymerization of nucleotides, amino-acids and sugars all involve dehydration elimination of H2O, giving water a central role in polymer formation.
P and S as Low-energy Covalent Modifiers - the delicate role of Silicon.
The second-row covalent elements are sub-optimal in their mutual covalent interactions and their interaction with H. Their size is more compatible with interaction with O, forming e.g. SiO32-, PO43- & SO42- ions including crystalline minerals. The silicones are notable for their O content by comparison with hydrocarbons. However in the context of the primary H-CNO interaction, two new optimal properties are introduced.
PO43- is unique in its capacity to form a series of dehydration polymers, both in the form of pyro- and poly-phosphates, and in interaction with other molecules such as sugars. The energy of phosphorylation falls neatly into the weak bond range (30-60 kj/mole) making it suitable for conformational changes. The universality of dehydration as a polymerization mechanism in polynucleotides, polypeptides, polysaccharides and lipids, the involvement of phosphate in ATP energetics, RNA and membrane structure, and the fact that the dehydration mechanism easily recycles, unlike the organic condensing agents, give phosphate uniqueness and optimality as a dehydrating salt.
The function of S in biosystems highlights a second optimality. The lowered energy of oxidation transitions in S particularly S-S ´ S-H , by comparison with first row elements, gives S a unique role both in terms of tertiary bonding and low energy respiration and photosynthesis pathways.
It has recently been discovered that oligoribonucleotides will polymerize effectively on silicate clay surfaces, where the positive ions of atoms such as Al make polar interactions with the phosphate backbones of RNA, stabilizing the molecules and making further polymerization possible in an ordered geometry. This consitiutes a major breakthrough in the modelling of life's origins and demonstrates the sensitivity of the biogenic pathway to the subtle differences of electronegativity of the second-row covalent elements phosphorus and silicon.
Ionic Bifurcation.
The cations bifurcate in two phases : monovalent-divalent, and series (Na-K, Mg-Ca). Although ions such as K+ and Na+ are chemically very similar, their radii of hydration differ significantly enough to result in a bifurcation between their properties in relation to water structures and the membrane. Smaller Na+ and H3O+ require water structures to resolve their more intense electric fields. Larger K+ is soluble with less hydration, making it smaller in solution and more permeable to the membrane (King 1978) . Ca2+ and Mg2+ have a similar divergence, Ca2+ having stronger chelating properties. This causes a crossed bifurcation between the two series in which K+ and Mg2+ are intracellular, Mg2+ having a pivotal role in RNA tranesterifications. Cl- remains the central anion along with organic groups. These bifurcations are the basis of membrane excitability and the maintenance of concentration gradients in the intracellular medium which distinguish the living medium from the environment at large.
Transition Element Catalysis
These add d-orbital effects, forming a catalytic group. Almost all of the transition elements e.g. Mn, Fe, Co, Cu, Zn are essential biological trace elements (Frieden 1972), promote prebiotic syntheses (Kobayashi and Ponnamperuma 1985) and are optimal in their catalytic ligand-forming capacity and valency transitions. Zn2+ for example, by coupling to the PO43- backbone, catalyses RNA polymerization in prebiotic syntheses and occurs both in polymerases and DNA binding proteins. Both the Fe2+-Fe3+ transition, and spin-orbit coupling conversion of electrons into the triplet-state in Fe-S complexes occur in electron and oxygen transport (McGlynn et. al. 1964). Other metal atoms such as Mo, Mn have similar optimal functions, e.g. in N2 fixation.
Fig 3 : (a) The perturbing effect of the neutral weak force results in violation of chiral symmetry in electron orbits. Without perturbation (i) the orbits are non-chiral, but the action of Zo results in a perturbing chiral rotation. (b) Autocatalytic symmetry-breaking causes random chiral bifurcation (i). Weak perturbation results in only one chiral form (iii) (King).
Chirality bifurcation.
Although the electromagnetic force has chiral symmetry, the electron also interacts via the neutral weak force when close to the nucleus. This causes a perturbation to the electronic orbit causing it to become selectively chiral, fig 3(a) (Bouchiat & Pottier 1984, Hegstrom & Kondputi 1990). In a polymeric system with competing D and L variants, in which there is negative feedback between the two chiral forms of polymerization, making the system unstable, the chiral weak force provides a symmetry-breaking perturbation. In a simulation, fig 3(bi) high [S][T] causes autocatalytic bifurcation of system (ii), resulting in random symmetry-breaking into products D or L. Chiral weak perturbation (iii) results in one form only. The selection of D-nucleotides could have resulted in L-amino acids by a stereochemical association (Lacey et. al. 1988).
Inner Circles New Scientist 8 Aug 98 11 reports on findings that there is a 17% net circular polarization in light in gas clouds in the Orion nebula where new stars are forming. Although this was infra-red light James Hough says it should also apply to the ultra-violet light. This would explain the excess of L-amino-acids found in the Murchison meteorite, suggesting a cosmic rather than accidental origin for the handedness of biological molecules on earth.
Polarized Life Sci Am Oct 98
Tertiary Interaction of Mineral Interface.
Both silicates such as clays and volcanic magmas have been the subject of intensive interest as catalytic or information organizing adjuncts to prebiotic evolution. Clays have been proposed as a primitive genetic system and both include adsorbent and catalytic sites. The mineral interface involves crucial processes of selective adsorption, chromatographic migration, and fractional concentration, which may be essential to explain how rich concentrations of nucleotide monomers could have occurred over geologic time scales.
More recently a fundamental interaction between RNA and clays has been elucidated wich appears to be central in enabling oligo-ribonucleotides to polymerize in an ordered way while bound to the positively charged metal groups in montmorrilonite clays, bridging the gap between small random ribo-oligomers and RNA molecules of a length capable of self-replication.
Key polymerizations
Key polymerizations such as those of HCN and HCHO are proposed to generate a series of generic bifurcation structures through combined autocatalytic and quantum bond effects, which include major components of the metabloism including nucleotides, polypeptides and key membrane components. These will be examined in the next section
The astronomical perspective

The occurrence of the key precursors of biomeolecules are not in any way confined to Earth of the specific conditions of Earth. Much of the organic material on earth is believed to have peppered down from comets and carbonaceous meteorites especially earlier in the evolution of the solar systems when less of the original material from the proto-solar gas and dust cloud had been swept away by collision. Protosolar gas clouds in the Orion nebula are known to contain precisely HCN and HCHO as shown above. Certain parts of the universe give off an infra-red signal not unlike that of carbohydrates. Interstellar dust grains are also known to contain organic molecules. In fact the occurrence of organic molecules is essentially ubiquiitous to all second generation sun-like stars containing a mix of elements of nucleosynthesis formed from the material of previous supernovas.
Indeed their presence is so commonplace and the incidence of life on Earth is so early that the possibility that arose previously to the formation of Earth cannot entirely be ruled out. Cosmological biogenesis is however ideally suited to the conditions actually occurring on Earth with plentiful water, a temperature just above the liquefaction of water, a good supply of organic molecules and a steady mild solar input.

Just as one can consider the non-linearities of the electromagnetic force in developing the fractal dynamics of molecules, one can also appreciate the significance of non-linearities in gravitation in forming the rich diversity of planets and satellites we see in our own solar system. Other stars now seem to be quite richly endowed with planets, but these again show very marked variation. Such marked variationis characteristic of non-linear dynamics, which serves to accentuate existing differences for example in temperature and composition between the planets to cause unique effects, such as the highly acidic, electrified runaway greenhouse atmosphere of venus.
Far from considering these extreme variations as reducing the likelihood of finding life on other planets, what it demonstrates is that on an astronomical scale as well as the microscopic, the universe behaves very much like a Mandelbrot set in establishing dynamics of uniqueness and diversity which explores the dynamical space of possibilities.

The first stage of this path of increasing molecular complexity is the generation of organic molecules from simple precursors such as the primitve gasses that may have constituted the primal atmosphere. Although there has been some debate whether the primal atmosphere was actually as reducing as the original Miller-Urey experiments, there is likely to also have been a vast amount of organic matter deposited directly on the earth from astronomical impact during the earlier more active phase ofthe solar system. Recently millions of tons of buckyballs have been found deposited intact from space suggesting that such impacts could leave organic molecules realtively unscathed (see below).
The fact that a variety of energy sources from heat through spark chemical exudates from ocean vents, to solar radiation are all capable of generating the key monomers of the biosynthetic polymerization pathways lends weight further to the centrality of these pathways to the sturctural interaction of the four forces.

Central polymerization pathways from HCN, HCCH and associated molecules to purines, pyrimidines (the bases of RNA) to polypeptides and amino acids and to porphyrins (King).
Polymerization Complexity
The first section has already discussed how a variety of energy sources can give rise to organic molecules of a wide variety of types. Central to these polymerizations is a process where the high energy favours the formation of the multiple bonded forms - CC-, - CN, and > C = O because they are the strongest and hence most likely to survive high energies. These in turn become capable of further polymerization, because at low energies their multiple bonds are energetically liable to open to form chain and ring interactions. The wide variety of products of these types is illustrated above for HCN and HCCH and below fro HCHO. The products include both the pyrimidine and purine bases of nucleic acids, a variety of amino acids often joined as polypeptides, porphyrins and a wide variety of other organic molecules including many capable of performing further condensations.
These reactions are also capable of producing larger structures such as microcells (see top of article) which sometimes display the bilayer structure of lipid membranes in living cells. HCN can also aggregate to a less diverse 'black polymer', although the occurrence of this will depend on the reaction conditions. Understanding the products of these polymerizations is complicated by the quantum information paradox they present. The initial conditions consist of only a few simple molecules and the final conditions are a diverse array of increasingly complex polymers.
The simplified and highly ordered conditions of traditional chemical laboratory reactions are not well-attuned to handling such complexity and the great potentialities for feed back they present.
Recent developments
Stanly Miller in Nature June 95 also reported that they had synthesized copious ammounts of cytosine and uracil the two pyrimidine bases that had remained difficult under plausible prebiotic conditions from cyanoacetaldehyde and urea under conditions which simulated a warm tidal pool. This comes 40 years after Miller as a 23-year old graduate student first synthesized peptides and large amounts of the purine bases adenine and guanine by spark discharge of ammonia, hydrogen, water vapour and methane.
Although people have since suggested that this mixture did not occur on the primitive earth, which would rather have had a high CO2 atmosphere, the discovery by Jeffery Bada of "mother lodes of undestroyede buckyballs - soccer-ball shaped carbon polymers containing galactic helium arrived unburned in an early meterioid - confirms that large quantities of complex organic molecules would have reached the earth's surface.
Structural Features of the - CC-, - CN, and > C = O polymerizations.
At least three distinct factors are capable of influencing the products of the polymerizations of multiply-bonded forms:
Free Energies and Resonance: The lower energy configuration of key stable products such as adenine leads to their formation based on free energy considerations.
Stochastic Kinetics: Accidental kinetic association between initial molecular species may form an organizing centre for subsequent structural evolution. For example, the HCN dimer is a key bifurcation point in the reaction. Stochastic kinetics ultimately derives its indeterminacy from quantum uncertainty.
Autocatalytic Bifurcations: Products of increasing complexity such as polypeptides and polynucleotides may generate autocatalytic pathways which alter the structural-stability of the polymerization to favour certain types of product. Polypeptides and polyribonucleotides both provide a rich variety of possibilities for autocatalysis through non-random association factors during polymerization.
Cyclic terminators: Both the HCN and HCHO polymerizations have prominent cyclic products which act as spontaneous terminators of polymerization, because the self-interaction of cyclization terminates oligomerization by removing the principal reactive moieties. The purines, pyrimidines, ribose and porphyrins all display structure consistent with being cyclic terminators. Eschenmoser (1992) has discovered that the phosphorylated oligo-aldehydes have a selective propensity to form ribose. These conditions coincide precisely with those we would expect to occur during nucleotide formation and oligomerization as a result of phosphate dehydration.

Sample HCHO polymerization routes (King). Phosphorylation of the oligo-aldehydes causes the reaction to favour ribose, explaining how ribose could have been selected by the presence of phosphate energy. (Eschenmoser 1992).
Ribonucleotides as Universal Stability Structures
Adenine is one of the principal thermodynamic products of HCN polymerization. Guanine is also formed from the same pathway. The cross-reaction of HCCH with HCN leads to a direct synthesis of the pyrimidines. The synthesis of pyrimidines has recently been found by Miller to be strongly facilitated by the presence of urea, another component of the polymerization pathway. These stages are illustrated above.
Ribose is produced in HCHO polymerization in concentrations around 2%, but the polymerization of phospho-glyceraldehyde is selective for ribose, supporting the conclusion that ribose is itself a product of the same phosphate environment that facilitates nucleotide polymerization. The particular conformation of ribose as opposed to arabinose or the other sugars appears to be important in providing the free rotation of the base and phosphate moieties and the chirality of the resulting polymer.
The nucleotide unit, as exemplified in ATP, is a quantum stability structure linking cyclic oligomers of HCN and HCHO, [adenine and ribose are pentamers of each] linked via dehydration to the dehydration-mediating phosphate group which appears to be responsible for their linkage in the first place. This structure is further stabilized by water and Mg2+. In combination with the cosmic occurrence of HCN and HCHO, this gives RNA the potential status of a generic structure in cosmology, taking the form of a non-periodic linear polymer.
The fact that polymerizations of nucleotides, amino acids and sugars alike involve a common dehydration step similarly emphasizes the direct relationship between polynucleotides, polypeptides, polysaccharides and their monomers in the phase transition from aqueous to dehydrated.
There has been a great deal of debate about whether life could have started from RNA because it is relatively difficult to polymerize under ordered laboratory conditions and has types of self-affinity which can hinder replication. This has led to a variety of suggestions from genetic takeover, the idea that some other replicative process, for example replicating crystal defects in clays might have preceded and aided RNA replication, resulting in an RNA takeover. Other people have suggested that another type of polymer might have preceded RNA. Alternatives such as Orgel's peptide nucleic acids have been suggested as a potential basis of such thinking.
However many of these arguments stem from the very difficulties experimentalists place in the way of their own understanding, by reducing their model systems to simplified controlled conditions which cannot then display the more convoluted feedback responses displayed by the wider environment, which thmselves can be very selective, as evidenced by natural separation processes such as chromatography. The fact that it has taken so long to discover the the role of the mutual interaction of clays in stabilizing ribonucleotide polymerisation emphasizes this point.
The real lesson of the evolutionary behaviour of ribozymes devised y Szostack and his co-workers, which we discuss next, despite depending on clonal selection techniques is that RNAs are very capable of strongly adaptive responses, when allowed wider behavioural interaction than simple liear polymerizations.
Informational phase transition
The key idea about the development of replicative life is that it is a fractal negentropic phase transition. We have seen that the central biological polymerizations involve dehydration. The energy currency for nucleotide polymerzation is the phosphate energy of ATP. Usually prebiotic reserchers look for an energy metabolism to support life, generally a catalytically complicated and indirect heterotrophic chemical conversion.
However it is much more likely that the initial emergence of genetic replication arose directly from an informational phase transition, rather than indirectly from a metabolism. Even today, a virus outside a cellular metabolism functions only as information. Certainly viral replication requires energetic cellular enzymes and substrates. Nevertheless the role played by the virus is precisely to produce an informational phase transition in the cell.
The essential dilemma of RNA polymerization is how information should increase (and entropy decrease) by a dehydration polymerization in an aqueous medium. RNA is energetically prone to hydrolysis, because of the free energy of dissociation of its monomers. The answer to this problem is that the aqueous medium has to be in repeated phase transition from aqueous to dehydrated. If we combine a medium in which the primal polymerizations are producing reasonable quantities of the purine and pyrimidine bases and ribose (which itself requires a high-phosphate milieu) we are led to a high phosphate dehydrating environment typified by the margins of evaporating ponds, the 'salinated' ocean edge etc. These could lead directly to the formation of oligophosphates and hence high-energy pyro-phosphate bonds typified by ADP and ATP.
It has recently been found that RNAs can be polymerized to large enough oligomers to support the replicative process by forming a binding association with silicate clays, because of the interaction of the positively charged metal groups in the clay with the phosphate groups in the oligonucleotides. This allows a geometrical stability to the polymerization process as well.
A natural model for fratal phase transition thus consists of the following four components:

1. A micro-environment which is rich in phosphate and receives a relatively strong mix of oligomers of aldehyde and cyanide polymerization providing the four bases and ribose.
2. Sufficient dehydrated phosphate energy to form a variety of short ribonucleotide oligomers.
3. An intermittently dehydrated clay interface where these relatively random short oligomers can be bound to clay in a more ordered way and thus polymerize to polymers of up to 50 units in a selective complementary manner.
4. An RNA phase which permits catalytic and self-replicative cross-interaction of RNAs and their catalytic effects on other mlecules such as polypeptides.

The RNA Era
Like proteins, RNA is capable of forming tertiary structures as illustrated for tRNA, partly through H-bonding to the free OH group in ribose. Catalytic activity of polynucleotides, including transesterification, hinges on proton transfer . A popular concept concerning the development of genetic specificity is that the combined roles of RNA as a genetic replicator and catalyst through its tertiary structure solves a fundamental problem concerning the order of appearance of nucleic acids and coded proteins. In this model an RNA era preceded coded enzymes, in which simple replicative and enzymatic process based purely on RNA catalysis maintained a simple form of evolutionary biochemistry.

Fig 6 : Nulceotide coenzymes remain ubiquitous to modern energy metabolisms and attest to the primary involvement of nucleotides as active moieties: (a) Nucleophilic attack of adenine N9 on ribose. (b) MgATP-complex illustrates linkage between primal stability structures. Cyclic pentamers of HCN (adenine) and HCHO (ribose) are linked by phosphate dehydration, stabilized by cation and water structures. (c) Heterocyclic form of heme. Porphyrins have also been detected in primal syntheses. (d) Nicotine-adenine dinucleotide illustrates a possible ancient molecular fossil from the RNA era. (e) Cyancobalamin - vitamin B12. Eschenmoser (1988) has discovered a plausible prebiotic stability structure generating the complex B12 molecule which involves two nucleotides and a Co-porphyrin (King).
RNAs which can partially replicate
A new perspective has developed from the discovery of spontaneous splicing of RNAs in living systems and the capacity of such RNAs to function as catalysts in RNA-RNA reactions. The experimental demonstration using the G-rich template sequence of the Tetrahymena rRNA intron core to act as a C polymerase, converting C5 is into C4 and C6 has made the idea of the RNA world before proteins a natural hypothesis. The model has been extended to others for RNA-based error-correction, synthetases and the ribosome.

The ribosome showing the large and small subunits and the step by step formation of a new
amino-acid subunit of a protein chain, using transfer tRNAs curled, each with a specific
triplet code, and coded messenger mRNAs horizontal (Watson et. al.).
The ribosome consists of three types of RNA subunit the mRNA which codes the message the large and small rRNA subunits and the short tRNAs which code each amino acid to a particular triplet code of nucleotides. The ribosome, itself one of the most complex pieces of molecular machinery in the cell, containing over 50 protein units in its two-component structure, has proved capable of carrying out the essential act of translation even when virtually all of the proteins are stripped off indicating that the RNA components are not a mere scaffolding used by proteins, but the catalytic core of the process. This is consistent with the idea that the ribosome was originally a way that RNAs instructed and made proteins directly and autonomously.
Modified ribozymes have proved capable of acting as polymerases which can replicate complements to subsections of themselves. Experiments from Szostak's group give the clearest indication to date of how RNA-based replication might occur. Experimental cloning and mutation of a variety of RNAs has successfully evolved RNAs with extensive catalytic powers including partical self-assembly..
Replication in a Fractal Phase Transition
The sunY polymerase illustrates fractal RNA dynamics which could both explain the difficulties facing non-enzymic syntheses and illustrate how RNA replication developed prebiotically. The polymerization is structurally a three-level fractal process:
(a) The catalytic RNA is itself composed of separate subunits each of whose structures is simpler and shorter than the assembled enzyme, both permitting higher error rates and providing less competing secondary structure.
(b) On a second fractal level the subunits have as complements a collection of small oligomers which are small enough for any variant to exist in acceptable concentrations but long enough to provide specific binding regardless of predominant base type.
(c) Finally the oligomers require synthesis from individual nucleotides. For oligomers of length up to 4 or 5 this could be random single-stranded polymerization without reducing concentrations by more than 3 orders of magnitude. For longer oligomers a catalysed reaction using oligomer templates could maintain a non-random population of suboligomers of a multi-unit catalytic RNA. The onset of replication is then naturally modelled as a phase transition in the fractal dynamics.

Catalytic nucleotide interactions: (a) Phosphoimidazole. Proton transfers in (a) imidazole, (c) in base tautomerization, (c) in Tetrahymena intron. (d) Tetrahymena intron core is an oligo-C RNA polymerase, (e) trimer-mediated replication of modified hexameric RNA of self-complementary sequence, structure of the modified sunY modular RNA polymerase, (g) the ligation carried out on oligomers on the fragment C template (King).
RNAs polymerize proteins:
The major discovery that RNA appears to be the agent of peptide-bond synthesis in the modern ribosome and the capacity of modified ribozymes to act as amino-acyl esterases (Picarilli et.al. 1992) [the first step of ribosomal action] establish RNA can act as synthetase as well as transfer, messenger and ribosome. This gives RNA the capacity to act on its own to catalyse both its own replication and the ordered polymerization of proteins. Simpler model systems have also been advanced of the stereospecific capacity of D-nucleotides to act as a catalyst of L-amino acid polymerization. These results pinpoint RNA as the key prebiotic molecule generating ordered polynucleotide and polypeptide structures.
The development of RNA replication is modelled as a fractal phase transition. A central bifurcation pathway is coutlined, which could be capable of generating the major structural features of molecular biological evolution, including protein and nucleic acid structures, glycolysis, the tricarboxylic acid cycle, electron-transport, ion-pumping and the excitable membrane. These aspects of molecular evolution could thus be cosmologically general.
Recent developments
Following Thomas Cech's discovery of ribozymes, Jack Szostak and Charles Wilson revealed in Nature April 95 that they had made ribozymes capable of a broad class of catalytic reactions, not simply confined to the sugar-phosphate backbone of RNA, but including the peptide bonds of proteins and between carbon and nitrogen. They took between 100 and 1000 million 200 unit nucleotides and selected them for catalytic activity mutating and re-cloning the most successful candidates. Although the transesterficiations are as likely to snip RNA as join it David Bartel has developed ribozymes which can stitch together RNA oligomers without breaking the larger molecules.
Szostak and Eric Ekland and David Bartel argue in Science July 95 that although they have selected such ribozymes out of trillions in lab selection experiments, the ease with which they were generated suggests they are almost certainly part of a vastly larger class of similar molecules which nature is capable of producing.

* Let There be Life New Scientist 6 July 96
* The World according to RNA Scientific American Jan 96
* Molecules of Ancient Life Born Again NS 17 Oct 98

It remains possible RNA has had a more primitive precursor. Leslie Orgel has also in Nature announced the formation of peptide nucleic acid PNA, which can serve as a template for its own replication and for formation of RNA from its subcomponents. However Jim Ferris reported in Nature May 95 that he had overcome basic problems in the polymerization of short RNA oligomers by making adenine oligomers 10-15 nucleotides long on positively charged motmorillonite clays which grew to 55 units on repeated washing with nucleotides. This bridges the gap by providing a potential source for large quantities of the oligomers similar to those used in Szostak's experiments.
Carl Woese doubts that RNA copying was the central mechanism because a study of RNA-copying genes from the diverse branches of the evolutionary tree display different solutions to this process. However the evidence of the RNA world is diverse.
Summary of evidence for the cosmoligical status of RNA

1. The ribonucletide inherits a structure linking the bases and ribose which are themselves both direct cyclic oligomers of cyanides and aldehydes observable in galactic gas clouds such as the Orion nebula.
2. Dehydration and phosphorylation are common factors in key bio-polymerizations, membrane lipid formation, glycolysis, ribose and nucleotide formation and nucleotide polymerization.
3. Ribonucleotides can be polymerized through interactions with common silicates forming a symmetry-splitting of polarity between Si and P and can catalyse their own formation through auto-catalysis and self-complementarity.
4. Remaining fossils of RNA metabolism appear to exist in the nucleotide cofactors which pervade the electron transport chain, fatty acid synthesis and the tricarboxyllic acid cycle and in the RNA-based action of the ribosome.

UNIVERSAL STABILITY STRUCTURES IN MOLECULAR BIOLOGY
The previous discussion of the RNA era highlights a problem that is central to the form of molecular biology - how did the central molecular biological structures become generated, starting from a simple RNA-based genetic system? The traditional viewpoint is that they were successively created during evolution through mutations building one-by-one the protein components necessary to make a working whole. This however does not explain how systems as electron transport and the citric acid cycle could have functioned with only a partial complement of enzymes. A further problem is how such enzymes would be advantageous and evolve selectively if the system they were supporting did not function in some form without coded enzymes.
The alternative thesis is that many of the major features of molecular biology have arisen in parallel as generic structures through bifurcation, independently of the emergence of RNA, and were subsequently captured by genetic takeover as genetic complexity permitted. The candidates for this primal status as stability structures include the following : The polymeric structure of proteins and RNA, the form and function of nucleotide coenzymes, bilayer membrane structure and the topological closure of the cellular environment, ion transport, concentration gradients in the cytoplasm and excitability, membrane-bound electron transport, glycolysis and the citric acid cycle.
Such a parallel model requires mutational evolution as a takeover process in fixing these stability structures into the biological scheme, but also has far-reaching conclusions concerning the generality of molecular biology in cosmological terms, for while the details of mutational evolution would be unique to each environment, the major features underlying biology would be universal.
Nucleotides and the Nucleotide Coenzymes
In addition to the key role of ADP and ATP as energy currency in the bio-metabolism, the other nucleotides have generic roles which may predate the development of coded proteins. GTP for example is used selectively in protein elongation, in the ribosome, and the nucleotides UDP and CDP are generically selective as carriers of glucose and choline and other membrane components respectively, suggesting an RNA-based selectivity for each of these classes of molecule during the RNA era. Model prebiotic reactions have successfully coupled UDP and CDP to glucose and choline (Mar et. al. 1986). Similarly other nucleotide coenzymes have generic roles consistent with a primal function. Both NAD, fig 11(a), and FAD function as carriers of redox energy through ring bond transformations, coupling H on the nicotine and flavin bases. Coenzyme A consists of adenosine coupled to pantothenic acid and functions as a carrier of acyl and other groups via the terminal SH bond (Reanney 1977). Although CoA is currently used in different processes, its structure is consistent with an initial role in pre-translatory protein synthesis. The pantothenic acid moiety appears to be a molecular fossil of two such polymerized amino acids. Vitamin B12 also illustrates how a dinucleotide could bind an Fe-porphyrin ring, lowering its Fe2+- Fe3+ activation energy and thus form a carrier of electrons. Such coenzymes would extend the nature of phosphorylation energy by linking it to H+ and e- transfer reactions, hydride ion, and peptide transfer, consistent with a model for RNA-based electron transport involving Fe-porphyrins, FeS groups, FAD & NAD.

Fig 9 The genetic code contains evidence for several primal bifurcations. Centre position AU selects polar/non-polar as broad groups. VLIP are Val-Leu-Ileu-Phe. First position G determines primally abundant amino acids. Subsequent bifurcations include H-bonding block and acid-base (King).
The Form of Translation
The discovery that ribosomal, synthetase, messenger and transfer functions of protein synthesis can all in principle be carried out by RNAs without proteins leads to a natural interpretation of the development of the genetic code from a protein-free translation system. The major partitions of the genetic code have structural features consistent with an origin in underlying chemical bifurcations. The fundamental bifurcation sequence, fig 9 which should be read in conjunction with the bifurcation scheme for the amino acids in 5.1 is as follows:

1. Polarity bifurcation: There is a major bifurcation in polarity between amino acids with anticodons having centre bases U & A. Uracil is correspondingly more hydrophilic than adenine, as reflected in their dominant split in hydrophobicity A(3.86)>G(2.3)>C(1.5)>U(1.45) and water solubilities A=1/1086, U=1/280. This leads to the idea that the polarity bifurcation was a principal symmetry-breaking factor in the origin of the nucleic acid code (King 1982), consistent with the polarity bifurcation of the amino acids in 5.1.1.
2. Abundance and GC: The initial base G also codes the most abundant amino acids, consistent with a GXY code starting with GAY=polar (anticodon U), GUY=non-polar (anticodon A) providing binding strength of GC and frame shift suppression (Y=pyrimidine).
3. The fourfold code: Extending to include GGY, GCY, provides a fourfold specificity for polar (Asp/Glu), non-polar (Val and larger), along with Gly, and Ala as most abundant.
4. The eightfold code: This could have then doubled to and 8-word code by including CAY, CUY, CGY, and CCY coding for non-polar and basic groups.
5. The H-bonding block: OH- and SH-containing amino acids also appear to form a single additional block (UA)(GC)Y, suggesting a third bifurcation for H-bonding, with UAY reading stop.
6. Evolutionary takeover: The development of translation becomes an evolutionary process. Later assignments such as Arg and Trp are random mutational fixations.

Recent development:

* Genetic Code is Top Translator New Scientist 18 April 1998

The Membrane, Excitability and Ion Transport
The structure of the bilayer membrane is a direct consequence of the polarity bifurcation. The formation of amphophilic lipid-like molecules, based on a linear hydrocarbon non-polar section combined with an ionic or H-bonding polar terminal, leaves 2 degrees of freedom for layer formation. Backing of the non-polar ends completes the bilayer. Cell structure then arises directly from budding of the bilayer, as illustrated in budding in several types of prebiotic reaction medium. The use of CDP associated with choline, inisotol & lipids in membrane construction is consistent with membrane formation in the RNA era. The structure of typical biological lipids such as phosphatidyl choline display a modular structure similar to ATP, consisting of fatty acid, glycerol, and substituted amine again linked by dehydration and involving phosphateThe existence of the membrane as a non-polar structure leads to segregation into ionic and non-polar regimes. Ion transport is essential in maintaining the concentration gradients that distinguish the cytoplasm from the external environment and thus must develop in the earliest cellular systems (MacElroy et. al. 1989). Ion transport is a source of significant electronic effects, because the membrane under polarization is piezo-electric and is capable of excitation in the presence of suitable ions. Model systems using the simple 19 unit oligopeptide Na-ionopore alamethicin and artificial membranes display action potentials (Mueller and Rudin 1968). Similar results have been reported for microcells produced by prebiotic techniques containing light irradiated chromophores (Przybylski and Fox 1986), demonstrating that such effects are fundamental to the quantum architecture of lipid membranes (King 1990). Four groups of non-polypeptide neurotransmitters : acetyl-choline, catecholamines, serotonin and histamine are amines, the latter three being derived from amino acids tyrosine, tryptophan and histidine by decarboxylation. Two others are amino acids and thus also contain amine groups. Notably alamethicin also has glutamine amides located in the core of the pore (Fox & Richards 1982) consistent with a primal role for amine neurotransmitters in moderating ion flow through the membrane. The catecholamines are linked to indoles such as serotonin by a prebiotic pathway.

The amine-based neuro transmitters, comprising the indoles and the catecholamines have plausible primitive origins and are linked by a photo-induced quinone bridge, making it possible that membrane electrochemistry was also a very early development of living cells. Choline is also a quaternary amine and the membrane lipid hosphatidyl-choline has a similar aetiology specifically utilizing phosphate as a link between the components (King).
Electron Transport H+, e- & H2O
The fact that the proton is soluble in water to form the hydrogen ion, but the electron is not, unless attached to another group such as a quinone through reduction, causes a physical linkage to exist between the polarity bifurcation and the charge bifurcations associated with electron and proton transfer, fig 10(b). Despite the complexity of modern electron transport in photosynthesis and respiration, there is considerable evidence that membrane electrochemistry could have arisen before translation could produce coded enzymes. Firstly there is a consistent basis for the existence of many of the components of electron transport during the RNA era, since the nucleotide coenzymes NAD, FAD, a nucleotide-bound Mg & Fe-porphyrin ring similar to B12, a cysteine-bound FeS group (Hall et. al. 1974), possibly based on glutathione (g-glutamyl-cysteinyl-glycine) and quinones provide all the key components of electron transport in an RNA dependent but protein-free form, fig 10(e) (King 1990). Both porphyrins and quinones have obvious prebiotic syntheses and the primal role of nucleotide coenzymes has already been mentioned. Secondly, membrane structure and the solubility differences between the electron and proton guarantee a link between electron and hydrogen ion transport. Electron transfer does not require the coded active sites catalysing specific molecular transformations. Model systems using Fe-porphyrins and imidazole can couple oxidative electron transport to phosphorylation (Brinigar et. al. 1966) and photo activated Mg-porphyrin to phosphate link (Goncharova and Goldfelt 1990, Lozovaya et. al. 1990).
Glycolysis and the Involvement of Phosphate in Sugar Metabolism
Glycolysis forms a bridge between six and three carbon sugars, reversing the structural pathway from H2CO to the cyclic sugars, (see below). This is made energetically possible by phosphorylation, and releases high energy phosphate capable of driving other phosphorylations (Hermes-Lima and Vieyra 1989), fig 11(a). It is notable that the di-phosphorylation of fructose in glycolysis is homologous with the model route for nucleotide formation of fig 6(c). The high phosphate environment leading to RNAs would then naturally lead to similar phosphorylation of other sugars, and release of the high-energy phosphate bond through cleavage of the sugar. Mineral catalysis associated with phosphate gives the glycolytic pathway a natural basis for lysis of sugars as a dissipative structure. UDP-glucose coupling is also consistent with the involvement of glycolysis in the RNA era.

(a) Di-phosphorylation of sugars leads to glycolysis through interaction of charged phosphates. (b) Generic examples of group transfer in the tricarboxylic acid cycle (King).
The Tricarboxylic Acid Cycle
The tricarboxylic acid cycle forms a pool of multiply carboxylated molecules which carry CO2 in various states of energy, and result in reducing energy via nucleotide coenzymes NAD and FAD, which coupled with the use coenzyme A provide a coenzyme basis for the tricarboxylic acid cycle in the RNA era. This could have thus existed as a limit cycle of di- and tri-carboxylated molecules acting both as an acceptor of acetate (a carbohydrate-equivalent i.e. (H2CO)2) and as an emitter of molecular CO2 and reducing H, thus bifurcating carbohydrate level redox potential into reduced and oxidized components. The linkage to nucleotide coenzymes such as NAD would have served to create a bifurcation of redox potential in the molecular milieu contributing to the diversity of reacting species. This gives at least one possible role for Eigen's hypercycle concept however the process could have also been more chaotic, consisting of a population of molecules undergoing various generic transformations with net inflow of carboxylic acids and net emission of CO2 and transfer of H, due to generic transformations as illustrated in fig 11(b). Isomerization would have been catalysed by Fe2+. Several steps may have been driven by sunlight photolysis.

(a) A conventional heterotrophic origin based on glycolysis or a more primitive mechanism. All major features are developed randomly by mutational evolution. (b) Divergence of dissipative structures including major biochemical features is followed by capture via mutational evolution during the RNA era. A minimal genome is required because the dissipative structures have a spontaneous basis (King).
Genetic Takeover of the Generic Systems
The probability that the the central structures of molecular biology existed in the RNA era is consistent with their being chemical stability structures utilized by catalytic RNAs. The small genomes during the RNA era and limited catalytic capacity of RNAs by comparison with protein makes it likely that an RNA-based system had to capitalize on existing chemical stability structures without requiring enzyme-based biosynthetic pathways. Genetic takeover of the major features illustrated in fig 12(b) is consistent with such a limited role for RNA catalysis. However it also places these stability structures clearly in a category determined by cosmological symmetry-breaking, thus giving evolutionary biology a common pattern of inheritance on a cosmological footing. The model thus gives a more plausible account of the RNA era and makes specific predictions about the aspects of biology likely to be common to the universe at large.
The Terrestrial Record
Evidence fo life has been found in the earlist rocks leaving only a few hundred million years for life to form. The prebiotic syntheses of uracil and cytosine have been established by Miller himself, a prebiotically-plausible synthsis for RNA is emerging from Ferris's work and the selection of RNAs with catalytic activity has been amply demonstrated by Szostak and others. What was once a major impenetrable mystery is rapidly becoming a straightforward process.

Modern stromatolites (left), structures built of cyanobacteria (blue-green algae) grace Shark Bay, Australia. J William Schopf has found remnants of 3.6 billion-year-old stromatolites lying near fossils of 3.5 billion-year-old cells that resemble modern cyanobacteria,. resembling strings of microscopic cells (right). Life thus arose within the first billion years of earth's formation from the planetary disc (Scientific American Feb 1991).
First life on Earth survived battering by meteors New Scientist 9 Nov 96
In Nature (384 p 55) Gustaf Arrhenius studying tiny apatite grains in the Isua formation of Greenland has found carbon 12 to 13 ratios consistent with the grains originating from living matter.
The Isua rocks date from 3.85 billion years ago. Although indications from zircon crystals indicate a solid crust 4.2 billion years ago, no intact rocks have been discovered older than 3.96 billion years. The moon and probably the Earth likewise was heavily bombarded with meteors up to 3.8 billion years ago. This suggests that life evolved on earth as soon as environmental conditions allowed.

 

 Science & Mathematics

The Uncle Taz Library

Uncle Taz Home Page 2

  Site search Web search

powered by FreeFind