Genome of Extinct Steller’s Sea Cow Reveals Surprising Link to Human Skin Disease (Ichthyosis); Analysis of Ancient DNA from Sea Cow Bones Finds Genes That May Have Played Role in Adaptation to Cold Marine Environment and Yields Evidence of Long Population Decline

Steller’s sea cow was an extraordinary creature, an enormous, kelp-eating, cold-water relative of the dugong and manatee that was hunted to extinction within three decades of its discovery by Europeans. A new genomic analysis by an international team of scientists has now uncovered the genetic underpinnings of some of the most unusual features of Steller’s sea cows, including their thick, bark-like skin. The new findings, published February 4, 2022 in Science Advances, are based on ancient DNA extracted from the bones of 12 Steller’s sea cows. The researchers compared the sea cow genomes with a newly assembled genome of the dugong, its closest living relative, as well as with genomes of manatees, cetaceans, and other marine mammals. Demographic analyses of the sea cow genomes enabled estimates of past population sizes and indicated that the population of Steller’s sea cows had been in decline for a long time before it was pushed to extinction in the 18th century. The open-access article is titled Genomic Basis for Skin Phenotype and Cold Adaptation in the Extinct Steller’s Sea Cow.”