Stochastic linkage

In many species with heritable sex determination, the sex chromosomes are heteromorphic. Furthermore, in most systems with large non-recombining regions, the heteromorphic chromosome has accumulated a high number of deleterious alleles. Finally, it is well established that many loci that exist on the X have been completely lost from the Y (Ohno 1967). In phylogenetic […]

Evolution of recombination modifiers

Low rates of crossover between the X and the Y seems to be one of the defining characteristic of sex chromosomes (Harkess et al. 2017; Vicoso, Kaiser, and Bachtrog 2013). One hypothesis can adequately explain limited crossovers on part of the sex chromosomes: if the appearance of separate males and females in a population of […]

Early studies of sex chromosomes

At the turn of the twentieth century, evidence supporting chromosomes as the material basis for heredity cemented Mendel and Darwin as the grandfathers of a nascent discipline: evolutionary genetics. The switch in biology to a molecular basis for heritability and for evolution left a massive gap in theory in the field, but also opened a […]