Population Genetical, Behavioural and Evolutionary Studies in the Drosophila bipectinata Species Complex

Abstract

Comparison of population dynamics with regard to chromosomal arrangements, protein and nucleotide polymorphism among closely related species can provide invaluable glimpses into the intricacies of speciation. In addition, recently
diverged closely related species may also exhibit behavioural differences especially sexual behaviour which can be compared across the species and eventually may aid in understanding the process of speciation. To get the finer details of the so called ‘speciation genes’, evolutionary studies pertaining to hybrid incompatibilities are required. This involves detailed mapping of the speciation genes through introgression of a candidate gene from one species into the genetic background of another species. Evolutionary studies also include studies on the degree and pattern of sexual isolation among closely related species.
The Drosophila bipectinata species complex comprises four species namely, D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae. In three members of this complex i.e. D. bipectinata, D. malerkotliana and D.
pseudoananassae, subspecies have been identified. This complex with its species and their subspecies is a good model for speciation studies and has been extensively utilized for the purpose. This review attempts to compile all the important population genetical, behavioural and evolutionary studies that have been done in this complex so far. Eventually, we have also discussed what is still left to be done and the prospects of this complex being used in future to get answers relating to speciation.