AP Bio: Genome Blog 7, Chromosome 8: Self-Interest

In "Chromosome 8: Self-Interest," Ridley begins the ninth chapter of Genome by quoting Richard Dawkins' The Selfish Gene, which says, "We are survival machines - robot vehicles blindly programmed to preserve the selfish molecules known as genes.  This is a truth that still fills me with astonishment" (122).  Ridley goes on to explain that 97% of the human genome are not true genes but are junk or selfish DNA, which is "not just a passenger, whose presence adds to the size of the genome and therefore to the energy cost of copying the genome" (128).  Also, selfish DNA threatens "the integrity of genes" (128) through mutation.  Ridley ends the chapter with an account of the Pitchfork case - where two identical samples of semen from the bodies of two girls who had been raped and killed helped to find and convict the murderer, proving the value of genetic fingerprinting.