Microsatellite polymorphism based genetic variation in two sympatric species of Drosophila: D. bipectinata and D. malerkotliana

Drosophila bipectinata and D. malerkotliana are found to be distributed all along the Oriental-Australian continents and have common phylogenetic descent. The genetic divergence of these two species have been studied by using genetic markers like chromosome inversions and allozyme variants to establish the extent of variation they have experienced since their speciation. In this study, microsatellite variations have been considered to observe the genetic differentiation among the seven natural populations of D. bipectinata and six populations of D. malerkotliana. Results pertaining to both the species indicate that the level of average heterozygosity increases from north to south. Distinct genetic differentiation has been observed between north and south populations of both the species giving an indication that north and south populations have undergone genetic structuring due to absence of gene flow between them and varying environmental conditions. Based on the frequencies of microsatellite variants of the two species, we have computed the level of variation between these two species. The analysis in this regard shows an almost similar trend of genetic variation being experienced by these two species which could be a kind of parallel evolution occurring due to similar ecological niches occupied by them and similar impact of evolutionary forces.