iScience (2020-10-01)

An Indo-Pacific Humpback Dolphin Genome Reveals Insights into Chromosome Evolution and the Demography of a Vulnerable Species

  • Peijun Zhang,
  • Yong Zhao,
  • Chang Li,
  • Mingli Lin,
  • Lijun Dong,
  • Rui Zhang,
  • Mingzhong Liu,
  • Kuan Li,
  • He Zhang,
  • Xiaochuan Liu,
  • Yaolei Zhang,
  • Yuan Yuan,
  • Huan Liu,
  • Inge Seim,
  • Shuai Sun,
  • Xiao Du,
  • Yue Chang,
  • Feida Li,
  • Shanshan Liu,
  • Simon Ming-Yuen Lee,
  • Kun Wang,
  • Ding Wang,
  • Xianyan Wang,
  • Michael R. McGowen,
  • Thomas A. Jefferson,
  • Morten Tange Olsen,
  • Josefin Stiller,
  • Guojie Zhang,
  • Xun Xu,
  • Huanming Yang,
  • Guangyi Fan,
  • Xin Liu,
  • Songhai Li

Journal volume & issue
Vol. 23, no. 10
p. 101640

Abstract

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Summary: The 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 of S. chinensis chromosomes from its cetruminant ancestor and elucidate the evolutionary history and population genetics of two neighboring S. chinensis populations. We found that breakpoints in ancestral chromosomes leading to S. chinensis could 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.

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