2008/01/18

The Genomic Contract

The concept of the social contract (or compact, as some prefer), developed by such political philosophers as John Locke and Jean-Jacques Rousseau, heavily influenced the Founders. It describes a society as the result of a kind of unwritten contract among its adult members to cooperate and not prey on one another, who pool their powers and jointly decide to delegate some of those powers to agents who function as a government.

In 1976 Richard Dawkins wrote The Selfish Gene, in which he developed the concept that the fundamental unit selected for fitness in biological evolution is not the individual but the gene, and that it is a success strategy for genes to have their organisms sacrifice themselves to insure the survival not just of their own progeny, but of the genes they share with their relatives. This view of genetic evolution explains the advantage of individuals uniting in societies, because it is the society, more than the individual, that enables the survival of the genes shared by its members.

If we carry forward this gene-centric model of evolution, however, we see that it is not really "the gene" that is the fundamental unit. Genes mutate, and the mutations, if they make the organism more fit, tend to survive and yield "progeny" that are descended from them, but not the same. So it makes more sense to describe the fundamental unit not as a gene but as a genetic line of descent.

However, genes do not survive or propagate in isolation, any more than individual organisms do. It therefore makes sense to describe a genome as a kind of society of genes, united by a kind of contract, analogous to the social contract, which we may call the genomic contract. As a society, instances of genes cooperate to propagate the survival of a few copies of themselves, or mutated descendants. In multicellular organisms, especially those that reproduce sexually, most cells are nonreproductive and do not act to insure the survival of direct copies of their own genes, but the genes of cells differentiated to function as reproductive cells, in much the way that social species of organisms do.

Looking at genomes as societies of genes united by a genomic contract is not just a philosophic exercise. It can help us understand how genes are organized into genomes, how they adopt specialized roles, how they sacrifice themselves for the benefit of others, and even how they make collective "decisions". We may even be able to identify persistent transactions among them. We may be able to apply variations on economic, political, and anthropological models to help us understand them. We can speak of games with genes as players, and apply the methods of game theory.

This is only an introduction to the use of this concept. It is hoped that others will pick up on it and develop it further.

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