Interpopulation and interspecific divergence and selective process acting in orthologous genes fruitless and Odysseus in Drosophila mojavensis and Drosophila arizonae

Abstract

Speciation is one of the key events in the evolutionary process. In sexual organisms, speciation occurs when a reproductive barrier is established between two populations, preventing the cross between them. Such barriers may be pre-zygotic, limiting the potential for heterospecific mating through ecological, behavior, and mechanical incompatibility, or post-zygotic, in which the hybrids are not viable or show reduced fitness. The factors related to these processes are not fully elucidated, especially in relation to genetic changes related to the pre-and post-zygotic reproductive isolation. In this project, we propose to sequence, to evaluate the genetic variability and the selective process acting on two genes that may be related to pre- (fruitless) and post- (Odysseus) zygotic isolation in two closely related species of repleta group of Drosophila - D. mojavensis and D. arizonae. These species have interpopulation divergence at subspecies level, in the case of D. mojavensis, and varying degrees of reproductive isolation. The genetic divergence between the sequences of these genes candidates for "speciation genes" will be compared with the degree sexual isolation (times pre- mating and mating periods) and hybrid incompatibility (reduced productivity) between the two species, and incipient between populations in order to have better understanding the dynamics of speciation process in these species. (AU)