The Antarctic Weddell seal genome reveals evidence of selection on cardiovascular phenotype and lipid handling

Commun Biol. 2022 Feb 17;5(1):140. doi: 10.1038/s42003-022-03089-2.


The Weddell seal (Leptonychotes weddellii) thrives in its extreme Antarctic environment. We generated the Weddell seal genome assembly and a high-quality annotation to investigate genome-wide evolutionary pressures that underlie its phenotype and to study genes implicated in hypoxia tolerance and a lipid-based metabolism. Genome-wide analyses included gene family expansion/contraction, positive selection, and diverged sequence (acceleration) compared to other placental mammals, identifying selection in coding and non-coding sequence in five pathways that may shape cardiovascular phenotype. Lipid metabolism as well as hypoxia genes contained more accelerated regions in the Weddell seal compared to genomic background. Top-significant genes were SUMO2 and EP300; both regulate hypoxia inducible factor signaling. Liver expression of four genes with the strongest acceleration signals differ between Weddell seals and a terrestrial mammal, sheep. We also report a high-density lipoprotein-like particle in Weddell seal serum not present in other mammals, including the shallow-diving harbor seal.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antarctic Regions
  • Gene Expression Regulation / physiology
  • Genome*
  • Genome-Wide Association Study*
  • Lipid Metabolism
  • Oxygen / metabolism
  • Phylogeny
  • Seals, Earless / genetics*
  • Species Specificity


  • Oxygen