Chapter 36: Sexual Reproduction: The Recombination Functor

Sexual reproduction is formalized as a recombination functor from pairs of genotypes to a new genotype via meiosis. Beyond the primary self/non-self distinction, sex introduces a secondary boundary—self/other-self—within Life that enables combinatorial exploration of the fitness landscape. Crossing over and independent assortment generate genetic diversity far faster than mutation alone. The two-fold cost of sex is offset by faster adaptation, deleterious mutation purging, and parasite-driven frequency-dependent selection.