Inversion polymorphism in species of the Drosophila nasuta subgroup from Thailand

Abstract

Thailand populations of three species of the D. nasuta complex have been analysed for the presence of paracentric inversions. D. albomicans and D. sulfurigaster albostrigata were collected from Phuket, Chiang Mai and the River Kwai, whilst D. kohkoa was found only in Phuket and the River Kwai. Chromosomal polymorphism was studied in respect to geographical distribution. The Phuket populations of all three species proved to be highly polymorphic by comparison with the River Kwai and Chiang Mai populations. The heterozygosity frequencies of inversions were calculated and the variations interpreted as a result of adaptation to local ecogeographical conditions. Shared polymorphisms revealed that D. kohkoa and D. s. albostrigata are more closely related to D. albomicans than they are to each other.

Molecular characterization of inversion breakpoints in theDrosophila nasutaspecies group

“…In D. albomicans , chromosome 3 fused to both the X and the Y chromosome, forming a neo-sex chromosome. Inversion polymorphism of the nasuta species group has been studied using cytogenetic techniques (Casu 1990; Lambert 1982;Pope 1987), and species in this group were found to be highly polymorphic for chromosomal inversions. However, no systematic characterization of inversions at the molecular level exists.…”