Wednesday, October 12, 2011

A New Model of Molecular Evolution

       The key to the new theory of evolution, different from the standard model, is a new 'Darwinian' model of molecular evolution, overlooked in all models until now.

As explained, in the standard model, Darwin's force, natural selection, acts only via 'reproductive' success among living organisms; call it cellular evolution.  In standard theory, there is no force of, call it, 'replicative' success, acting directly on the non-reproductive component; call it molecular evolution.  If anything, most theories of molecular evolution are non-selective, neutral, or controversially, 'non-Darwinian', so let me explain how this came about.

The Standard Model of Molecular Evolution
       The standard premise is that molecular evolution exists only because of reproduction, or cellular evolution. It seems unimpeachable that organic molecules evolve because life evolves first, but this is still an ontological (chicken and egg) argument, not a mathematical one.

Instead, the mathematical dilemma is that molecular change evolves slowly, for billions of years, but reproductive change evolves rapidly, in tens, or hundreds of generations. Both time scales will not fit in a single frequency equation (later, I show how to solve this), so the frequency answer is to treat evolution as successive 'snapshots' over relatively short times.  Over short times, the molecular state in the first instant will seem fixed or static, from whence it will be modified by two forces, mutation and selection. In this model, genes mutate randomly, and selection multiplies favorable mutations, but it removes harmful ones, while neutral mutations will cause no change.

This model has been intensively studied, and it serves its purpose as a background to the standard model of reproductive change over short times. Over huge time scales however, this model does not work, and results in several paradoxes, which have never been solved.

1)   Any mutation, even a favorable one, increases disorder, and no amount of selection after the initial disorder can restore the balance, so total order can never increase (see Paradox 3 below).

2)   Similarly, over the history of life, order did not decay from an initial state, but it increased, if anything, in large, sudden steps.  It is a well-known paradox, however, that if even small mutations increase disorder, a large mutation producing a step increase in order is statistically impossible.

3)   A model that depends on a stable molecular state existing first cannot solve how life began from a state of pre-life, because prior to selection, the molecular state of pre-life must have been highly disordered. If anything, this is another well-known paradox, in which the molecular state of pre-life had a mutational load too high for life to begin anyway, and further mutation would only increase this load.

4)   Similarly, a model that depends on living reproduction existing first also cannot solve how life began, because by definition, pre-life must have been pre-reproductive. This initial paradox can be solved by separate, non-living selection (replication), but this makes the ontology of the mutation-selection model incorrect. In pre-life at least, not life (reproduction), but non-living selection (replication) has to exist first.  Later I will prove that fro every transtion, replication must precede reproduction, and not the other way araound.

5)   Finally, even its proponents admit that the standard molecular theory is 'non-Darwinian', so if the goal is to prove that life evolved by natural selection, this model cannot make a single prediction, to test this hypothesis.  Especially, the standard model teaches that in single populations a successful gene will maximize its distribution, or frequency.  Molecular evolution however, applies across all populations, but no mutation-selection model has ever predicted which genes will maximize their distribution across life, in ways that can be tested.

I will now propose a simple, testable, 'Darwinian' model, to solve all of these paradoxes.