A female Antarctic fur seal with her newborn pupJAUME FORCADAThe influence of climate change is already apparent in the genomes of Antarctic fur seals (Arctocephalus gazella) living in the southern Atlantic Ocean, according to a study published today (July 23) in Nature. Female seals with high heterozygosity—genetic variation between chromosome pairs—are more likely to join the breeding pool and to breed successfully than are more genetically homogeneous females. These traits are tied to the fluctuating supplies of the tiny krill that the seals eat. But they will not protect the animals as the climate continues to change, as they are not heritable, researchers report. Heterozygosity in breeding females has increased even as the fur seal population and birth weight have declined.
Ecological geneticist Ary Hoffmann of the University of Melbourne in Australia noted that previous work has shown that heterozygous animals typically have an advantage, especially under stressful conditions. “This seems to be . . . a nice illustration of an earlier phenomenon, but then placed in the context of climate change,” said Hoffmann, who was not involved in the study.
“Not many studies have analyzed the consequences of ongoing climate change on patterns of genetic variability, and I think that this study constitutes an unprecedented contribution [in] this respect,” Joaquín Ortego, an evolutionary biologist at the Doñana Biological Station in Spain, wrote in an e-mail to The Scientist.
Researchers have been monitoring fur seals on the island of South Georgia for more than 30 years. ...
