Biology

Dr. Neelesh Dahanukar
IISER Pune

Abstract:

Tectonic history of India for the last 100 million years is fascinating. This is partly due to several drastic events such as the split from the Gondwana, journey towards north of the equator, the Deccan volcanism and collusion with the Eurasia. While this journey has been linked to the incredible diversity of faunal and floral elements of India, their role in the biogeographical distribution and speciation in several taxa is limited. Molecular genetic techniques coupled with statistical hypothesis testing for alternative phylogeographical scenarios provides an excellent opportunity to predict ancestral distribution of extant organisms. Predicted ancestral distributions, coupled with molecular clocks, can help in reconstructing biogeographical history of India and provide new insights into molecular evolution and speciation events. Freshwater fishes form a unique system to understand the fine scale changes in tectonic activities because of their restricted distribution to river drainages. Our studies on the molecular phylogeny of hillstream loaches, barbs, catfishes, badids, glassfishes, sneakheads and killifishes provide new insights on the effect of continental drift, the Deccan trap formation, ancestral river linkages and geological barriers on the speciation and biogeographical distribution of fishes of India. Further, our analysis challenges some canonical views regarding Indian biogeography indicating a need for proposing and testing new hypothesis. Supported by other taxa, including amphibians and scorpions, we suggest that these biogeographical analyses can help in finding better priors for phylogeographical hypothesis testing of other taxa and may also provide new insights into the future of biological diversity in the Anthropocene.