The Extended Phenotype: The Long Reach of the Gene

The facts are as follows. The total amount of DNA in different organisms is very variable, and the variation does not make obvious sense in terms of phylogeny. This is the so-called ‘C-value paradox’. ‘It seems totally implausible that the number of radically different genes needed in a salamander is 20 times that found in a man’ (Orgel & Crick 1980). It is equally implausible that salamanders on the West side of North America should need many times more DNA than congeneric salamanders on the East side.

The whole purpose of our search for a ‘unit of selection’ is to discover a suitable actor to play the leading role in our metaphors of purpose.

Adoption and contraception, like reading, mathematics, and stress-induced illness, are products of an animal that is living in an environment radically different from the one in which its genes were naturally selected.

To the extent that active germ-line replicators benefit from the survival of the bodies in which they sit, we may expect to see adaptations that can be interpreted as for bodily survival. A large number of adaptations are of this type. To the extent that active germ-line replicators benefit from the survival of bodies other than those in which they sit, we may expect to see ‘altruism’, parental care, etc. To the extent that active germ-line replicators benefit from the survival of the group of individuals in which they sit, over and above the two effects just mentioned, we may expect to see adaptations for the preservation of the group.

Why are genetic determinants thought to be any more ineluctable, or blame-absolving, than ‘environmental’ ones?