River dolphins are evolutionarily distinct and threatened cetaceans inhabiting freshwater and estuarine ecosystems. They act as apex predators and play an important ecological role in aquatic food chains. They are threatened by river flow alterations and habitat fragmentation caused by dams, fisheries bycatch and targeted hunting, river pollution, and the lack of monitoring and effective protection of river ecosystems. Most of our knowledge of Cetaceans is derived from studies of species in the global north, though evidence suggests cetaceans evolved in the Indian subcontinent. India is home to about 32 such cetacean species. Among these, the Gangetic River Dolphins (GRD), Indus River Dolphin (IRD), and Irrawaddy Dolphins (IRR)are freshwater species, and the genomics of these species are poorly understood. A major challenge for cetacean studies in India has been that sampling these species is very difficult, and non-invasive sampling has not been optimized for Indian species. Several of these issues can be overcome with non-invasive sampling and high-throughput genome sequencing. Comparative genomic analyses also provide an opportunity to explore the basis of adaptive traits such as hypoxia tolerance, thermoregulation, and blood pressure homeostasis. Blood pressure homeostasis is a critical cardiovascular adaptation for life in aquatic environments, yet its evolutionary basis remains poorly understood, particularly in freshwater cetaceans.
My first chapter is a literature review where I aim to understand the distribution of cetaceans, research effort, and temporal trends in cetacean genetics and genomic studies.

In the second chapter, I am developing genetic resources, such as a reference genome and a species-specific SNP panel, and using them to estimate the population size.

In the third chapter, I estimate genetic diversity in the historical and contemporary population, their structure, connectivity, historic demography, and potential genetic threats.

My fourth chapter is about the adaptive evolution of blood pressure homeostasis genes and how they differ between marine and freshwater cetaceans.