Commentary on Richard Dawkins part 3

To add on further to the earlier debates on Richard Dawkin's work, The Selfish Gene, which I have posted on this blog, I would like to charter the path detailing the evolution of humans. Along the evolutionary timeline, it will be interesting to note that the human race encountered loss of function of certain genes. A more well-known candidate is L-gulonolactone oxidase, a key enzyme that produces vitamin C. The other candidates are your cytochrome P-450 enzymes, and some amongst us do not possess certain subtypes of cytochrome P-450 enzymes.

What does this mean? To begin, the human genome is subjected to daily insults, that results in mutations. Free radicals in the form of reactive oxygen species and electrophilic compounds can react with DNA bases, resulting in covalent modification and changing the base pairing rules that ultimately results in mutations.

Mutations can bring a selective advantage to the organism, or become detrimental to the organism, whereby tumors can arise as the result of multiple mutational hits. There are mutations that do not affect the organism drastically, or have negligeable effect. Consider the case of CYP (Cytochrome P-450) enzymes. Somewhere along our evolutionary past, these enzymes are crucial to the processing of foreign substances, rendering them harmless so that they could be excreted via the urine. However a number of genes encoding subtypes of CYP enzymes have accumulated a number of deleterious mutations, totally losing their functions. It doesn't affect humans that much either because there are other CYP enzymes that perform similar functions or we are no longer in contact with the harmful foreign substances in question. Similarly, in the case of Vitamin C, our ancestors carried the deleterious mutation in the gene encoding L-gulonolactone oxidase. However, our ancestors were not greatly affected because they might have migrated to a rich oasis where food rich in Vitamin C lies abundance.

What does my initial discussion has got to do with my discussion on Richard Dawkins? Well, the fate of whether a gene can be perpetuated in its unadulterated form (encode the functional product), lies in the dynamics of the organism's interaction with its environment in the face of encroachment by mutagens. The gene that encode L-gulonolactone oxidase would have been perpetuated if there is a scarcity of food containing Vitamin C, and organisms harboring deleterious mutations in the gene would have been extinct. Similarly, the genes encoding the functional subtypes of CYP enzymes would have persisted if the harmful foreign substances were to persist in our environment. Ironically, the inevitable process of mutation coupled with dyamics of the organism's interaction with the environment can be seen as a "rebellion" against the perpetuation of the gene in its functional form. Allow me to paint this scenario. For instance, a currently imaginary functional CYP gene known as CYP-Evolution101 encodes a product that converts an imaginary harmful substance Uraniumana-365 into a harmless substance. This Uraniumama-365 is ever present in the Earth atmosphere, and a deleterious mutation in CYP-Evolution101 would result in extinction of the mutants. However, one day Mankind feels that He has enough of staying on Earth. The entire Mankind makes a decision to permanently migrate to an imaginary planet named Socrates World. Uraniumana-365 is non-existent in Socrates World. Under the encroachment of mutations, there will be no love lost if CYP-Evolution101 encounters a deletional mutation. CYP-Evolution101 would be no more than a fossilized carcass in the human genome or would have faced total deletion from the human genome. A chance for Mankind to go one up in his "rebellion" against the gene indeed.

Yet when we speak of the perpetuating gene, we seemed to ignore the "internal rebellion" amongst genes themselves. What do I mean? Remember I mentioned earlier about deletional mutations in certain subtypes of CYP enzymes because there might be other CYP enzymes performing similar functions? Consequently, we are looking at a battleground at the genetic level, multiple number of genes performing similar functions competing for indefinite perpetuality, in the face of encroachment by mutations. Assuming there are 20 genes performing similar functions, and only a maximum of 3 are needed for the organism's surivial. The end result is that 3 of them would be perpetuated into succeeding generations, whilst the other 17 would be either deleted into oblivion or ended up being fossilized carcass in the genome.
The ongoing "rebellion" against the perpetuating gene has been waged amongst genes themselves, and at the macroscopic level involving the dynamics of the organisms' interaction with the environment, with the process of mutation joining in the fracas, and this has been ongoing since the evolutionary clock started ticking.