The genetic drivers for the successful invasive potential of a generalist bird, the House crow

What kind of genetic structure helps the rapid range expansion of the invasive species is fundamental to understand spread of invasion. The House crow (Corvus splendens), an ecological generalist, having a large native and introduced distribution range, is a good study model to investigate the genetic structure and adaptations underpinning the evolutionary potential for successful biological invasion. Thirteen mainland and one island native population from the Indian subcontinent were studied using four nuclear introns and mitochondrial genome to determine the phylogeographic structure and demographic history. A large, panmictic long-term expanding native population dating from the last glacial period (~ 30,000 ya) was inferred leading to great genetic diversity across the whole native range. The thirteen mitochondrial encoded proteins, directly involved in the energy supplying pathway, could underlie metabolic adaptations during range expansion under diverse climate conditions. Therefore, to investigate the molecular selection on these genes in native and introduced ranges, five previously studied introduced populations from Southeast Asia and Africa were included. The native populations originating from hot arid and humid tropical areas exhibited the signatures of positive selection on four codons located in three genes (ND5, Cytb and COX2), suggesting these may have evolved under environmental stresses in those regions. Our findings demonstrated the native range population as the reservoir of the species’ genetic diversity, mitogenomic patterns of the introduced populations related to native range of species and no varaints could be associated with climate in introduced range. Thus,inferred that the pre-adapted standing genetic variations evolved during dispersion over the native range are the predominant source of the high evolutionary potential and contribute to the successful invasion history. These findings will help to predict the future introduced range of the House crow.