Sex chromosome meiotic drive

Sex chromosome drive refers to the unequal transmission of X and Y chromosomes from individuals of the heterogametic sex, resulting in biased sex ratios among progeny and within populations, The presence of driving sex chromosomes can reduce mean fitness within a population, bring about intragenomic conflict between the X chromosome, the Y, and the autosomes, and alter the intensity or mode of sexual selection within species. Sex chromosome drive, or its genetic equivalent, is known in plants, mammals. and flies. Many species harboring driving X chromosomes have evolved Y-linked and autosomal suppressors of drive. If a drive polymorphism is not stable, then driving chromosomes may spread to fixation and cause the extinction of a species. Certain characteristics of species, such as population density and female mating rate, may affect the probability of fixation of driving chromosomes. Thus, sex chromosome drive could be an agent of species-level selection.