Narwhals Have Low Genetic Diversity—and They’re Doing Fine
by Brigit Katz Smithsonian.com
The lack of genetic diversity among animal populations is often seen as a sign of impending doom; without genetic variation, a species cannot adapt to changing conditions and will eventually go extinct. But narwhals are complicating this theory, the elusive, oddly-toothed whales are faring quite well in the wild. Last year, the IUCN changed the animals’ conservation status from “near threatened” to “least concern,” but as Sam Wong reports for New Scientist, a new study has shown that diversity in the narwhal gene pool is remarkably low.
For the new report, published in the journal iScience, a team of Danish researchers sequenced the DNA of a narwhal from West Greenland. By determining how closely one individual’s parents were related, scientists can reconstruct genetic lineages of ancestral populations, Wong explains. And the researchers found that genetic diversity among narwhals is low, as previous studies have also suggested.
In other species, reduced genetic variation has been attributed to inbreeding, which can happen when a population dwindles over time, or to more acute population bottlenecks, which are events, like an environmental crisis, that dramatically reduces population size and leads to the loss of gene variants within the population. But the narwhal genome lacked signs of inbreeding, according to the study authors.