Population Genetics of Drosophila: Genetic Variation and Differentiation among Indian Natural Populations of Drosophila ananassae.

Sanjay Kumar and Arvind Kumar Singh (2017) Genetic subdivision in natural populations of animals including Drosophila can be well understood by studying the role of evolutionary forces like natural selection, migration and genetic drift which are mainly responsible for the change in their genome. Drosophila ananassae is a cosmopolitan and domestic species and is one of the prevalently occurring Drosophila species in India. It occupies an important status in genus Drosophila due to its certain genetic peculiarities like spontaneous male meiotic crossing over, varied chromosomal polymorphism, Y-4 linkage of nucleolus organizer etc. and therefore, it seemed appropriate to investigate population structure and genetic differentiation among its natural populations. We assayed allozyme variation among 15 natural Indian populations of D. ananassae to evaluate its population structure and genetic differentiation. To test genetic differentiation between the populations, pairwise FST values were calculated and the results obtained clearly showed that Indian populations of D. ananassae are not homogeneous and exhibit moderate level of genetic differentiation. Nei's genetic distance (D) values were found to be positively correlated with geographic distance. Further, it was observed that South Indian populations of D. ananassae are genetically more similar to each other and showed substantial genetic variation from North Indian populations.