Some Models for Treating Evolution of Multigene Families and Other Repetitive DNA Sequences

During the last several years, molecular biology has undergone a second round of remarkable development. This has brought a number of new findings regarding the genetic organization of higher organisms, as distinct from that of lower organisms. One such discovery is the prevalence of multigene families and other repetitive sequences. For about ten years, I have been studying the evolution of multigene families from the standpoint of population genetics. Recently, I extended the analyses to treat repetitive DNA sequences that are dispersed in genomes. Repetitive sequences are characterized by concerted evolution, i.e., gene copies belonging to a family of repeating elements do not evolve independently, but evolve as a set through various molecular interaction mechanisms such as unequal crossing-over, gene conversion and duplicative transposition. By incorporating such interaction mechanisms, the population genetics model of an evolving multigene family becomes very complicated. In this paper, I shall review models and analyses on repetitive gene families.