The Tree of Life: Tangled Roots and Sexy Shoots: Tracing the genetic pathway from the first Eukaryotes to Homo sapiens

Abstract

The picture conveyed by the significance of endosymbiosis, genome fusion and horizontal transfer as key evolutionary processes complementing the vertical transmission of the tree of life, makes clear that evolution is not just a matter of competitive survival of the fittest gene, individual, or species, but of dynamic survival of genes in a surviving ecosystem. Although Dawkins' (1978) notion of the "selfish gene" was pivotal in drawing attention to the fact that it was the survival of genes and not organisms, or even species, that was the key evolutionary process, attributing the human sentiment of selfishness to a gene is somewhat of a self-serving advertising distraction on the part of the author, which diminishes the subtlety and complexity of the sometimes apparently paradoxical ways genes actually interact to bring about beneficial outcomes in the evolutionary dynamics of the ecosystem. Although the idea of selection of genes has been pivotal in defining the need to consider evolutionarily stable strategies under genetic variation in ways which have been subsequently confirmed time and time again in situations such as the sexual genetics of social insects such as bees and ants, social selection is by no means ineffectual, or much of sociobiology, including the biological basis of morality as an extension of reciprocal altruism, would cease to exist. Moreover, from what we have seen, particularly about horizontal gene transfer, and the capacity of mobile elements to induce modulated changes in nuclear genomes, it is not the 'selfishness' of a genetic element alone that results in survival of both a gene and its hosts, but dynamic feedbacks,, and relationships which ultimately contribute to a massive sharing of information in the manner of parallel genetic algorithms fundamental to the replicative genetic process, which enable global forms of genetic and genome optimization central to the overall viability of life as complex systems.