EVOLUTIONARY GENETICS AND GENETIC-VARIATION OF HAPLODIPLOIDS AND X-LINKED GENES

The evolutionary genetics of haplodiploids and X-linked genes share ma ny features and are different from diploid (autosomal) genes in many r espects. For example, the conditions for a stable polymorphism, the am ount of genetic load, and the effective population size are all expect ed to be quite different between haplodiploids or X-linked genes and d iploids. From experimental data, the genetic load for X-linked genes i s much less than autosomal genes and appears less for haplodiploids th an for diploids. The observed amount of molecular Variation for haplod iploids is much less than that for diploids, even more so than predict ed from the differences in effective population size. Extensive recent ly published data suggest that the differences in variation for X-link ed and autosomal genes for Drosophila, mice, and humans are consistent with the differences predicted theoretically based on the relative ef fective population sizes.