Population genetics of multigene families that are dispersed into two or more chromosomes

The evolution of multigene families whose members are dispersed into two or more nonhomologous chromosomes is studied from the standpoint of population genetics. By using a simple model of gene conversion, equilibrium and transient properties of the probability of identity of genes belonging to the family are investigated. Also, the time until fixation of a mutant belonging to a subdivided multigene family is studied by an approximation method. It is shown that dispersion of the family into two or more chromosomes has a relatively minor effect on the extent of identity between genes, unless the conversion rate between genes on nonhomologous chromosomes is extremely low, or unless the number of nonhomologous chromosomes on which gene members are dispersed is large.