RESUMEN
Altogether 11 geographic populations of Drosophila kikkawai were analysed from the viewpoint of karyotypic variation, inversion polymorphism and sexual isolation. The results revealed that of all the populations, the New Guinea population was the most genetically diverged, characterized by its distinct karyotype, possession of a fixed inversion, and its females exhibiting sexual isolation at the level of preferential mating. Based on these findings it was inferred that incipient speciation has proceeded in D. kikkawai and its New Guinea population is on its way to speciation.
Asunto(s)
Evolución Biológica , Drosophila/genética , Variación Genética , Animales , Inversión Cromosómica , Cruzamientos Genéticos , Femenino , Cariotipificación , Masculino , Nueva Guinea , Polimorfismo Genético , Conducta Sexual Animal , Especificidad de la EspecieRESUMEN
Drosophila kikkawai is a unique species in the genus, having two types of B-chromosomes with distinct centromeres. Laboratory experiments pertaining to their accumulation were carried out, using continuous selection and inbreeding procedures. Karyotypes with B-chromosomes ranged from 1 to 4. A maximum of four B-chromosomes in a culture were accumulated which seems to be the maximum tolerable limit in this species.