摘要：SummaryThe Indo-Pacific humpback dolphin (Sousa chinensis) is a small inshore species of odontocete cetacean listed as Vulnerable on the IUCN Red List. Here, we report on the evolution ofS.chinensischromosomes from its cetruminant ancestor and elucidate the evolutionary history and population genetics of two neighboringS.chinensispopulations. We found that breakpoints in ancestral chromosomes leading toS.chinensiscould have affected the function of genes related to kidney filtration, body development, and immunity. Resequencing of individuals from two neighboring populations in the northwestern South China Sea, Leizhou Bay and Sanniang Bay, revealed genetic differentiation, low diversity, and small contemporary effective population sizes. Demographic analyses showed a marked decrease in the population size of the two investigated populations over the last ~4,000 years, possibly related to climatic oscillations. This study implies a high risk of extinction and strong conservation requirement for the Indo-Pacific humpback dolphin.Graphical AbstractDisplay OmittedHighlights•Deducing chromosome evolution from ancestral Cetruminantia and ancestral Odontoceti•Reconstructing the demographic history ofSousa chinensis•Implying high risk of extinction and strong conservation requirement forS. chinensisEvolutionary Biology; Genetics; Genomics
