ADVANCING EVOLUTION THEORY

Thinking about evolutionary theory is a never endings source of idle time amusement for me. I am in the process of writing a book to discuss this thought that seems to be over looked or is side stepped; evolution shapes a background of chemical reactions; For example, enzyme proteins do not create chemical reactions or anything else but only facilitate and give directions to what is deterministic. Surprisingly, this chemical approach to evolution theory is a remarkably different because it has to start at the very beginning and not start at the usual Darwinian level of species. It has opened up many new avenues for me to explore.

With that in mind, I recently read a statement that Darwin’s “natural selection” has perfected certain proteins to do their jobs for as long as 3 billion years; enzymes, structural proteins, membrane proteins, cell signal receptors, cytokines, and hormones, etc. The idea is that evolution is an iterative process dependent on mutations; a cell produces a protein, which by chance happens to have nascent enzymatic or catalytic properties for some preexisting chemical reaction, for example. Of course, proteins do not just happen; there is a long complicated series of metabolic reactions involving nucleic acids and mysteriously generated series of chemical codes by chance. Mutations shape and change these spontaneously generated codes, which the primary protein structure reflects. If the change damages the inherent functionality of the protein, in this example, enzyme, the protein is not vertically reproduced, hence, the code is lost; however, if the mutation enhances the enzyme activity is enhance the change due to the mutation is preserved through vertical transmission; hence, perpetuated or preserved for future generations. Interestingly, if the mutation positively influences the catalyzed reaction in the cell, the cell is perpetuated as a unit. A mutation that damages, or retards the reaction is also enhanced hence leads to its own rapid demise by non-reproduction of the cell; thus, the same process that may enhance a reaction also may eliminate a change induced by mutation. The result is better and better enzymes through the perfection of functionality by “natural selection”; hence, three billion years of positive feedback is the essence of evolution.

What I was reading was a summary of what biologists refer to as the “caspase cascade” in an extremely well written book titled Power, Sex Suicide: Mitochondria and the Meaning of Life (2005) by scientist and author Nick Lane. The “caspase cascade” is a complex series of enzymes, one activating the next, ultimately leading to activation of an innate or genetically programmed mechanism of single cell death scientists refer to as apoptosis, in contrast to necrosis, which results from cell damage; thus, not programmed in cells. This enzyme enhanced caspase chain or cascade is only one of a number of similar series found in biology: coagulation ending in a clot or the activations of the complimentary system, which helps or “complements” the ability of antibodies and phagocytic cells to clear pathogens from an organism. The caspase cascade has an intrinsic and an extrinsic trigger just as the coagulation system does. This means the stimulus for activations of an enzyme or protein series can from the external environmental as well as internal environment.

This information stimulated the thought that natural selection has broader biochemical reach then I have ever considered; it applies to entire modules of genes and perhaps smoothly extends to the entire genome. The concatenation of beneficial mutations in the context of one protein is easy enough to understand but now consider series of mutations in “series” of proteins. The DNA code for each protein is perhaps thousands of nucleic bases in the genome for each protein and with multiply proteins involved, the scope of involvement of DNA is tremendously broadens, which is important because mutations are relatively rare. It makes the probability of rare events happening seem more “probable”. Scientists are more and more, considering living organisms to be the product of the entire genome and not just one gene; this realization of selection of mutations in series or cascades of proteins brings us one-step closer to that reality but adds to it at a more basic level and reinforces the Darwin concept of slow methodical evolution.

Apoptosis, or programmed cell death, is the result of an ever-broadening complex of proteins that has shaped our being, involving perhaps the shaping of our entire being. The classic but superficial example most often mentioned is the evolution of the hand, which maintains that the hand evolved from a form without fingers but because of apoptosis cells died leaving individual fingers in stark contrast to webbed feet as we see in sea mammals and some aquatic birds, for example. Advancing research opened a completely new field of what is still just wild speculation. I am excited to see where it will take us.   

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