Inbreeding Can Be Beneficial

The Svalbard reindeer, despite significant inbreeding and low genetic diversity, boasts a robust population of over 20,000, having adapted to Arctic conditions with unique traits like smaller size and the ability to digest mosses. Although they have evolved rapidly to past environmental changes, scientists fear the pace of current global warming may outstrip their capacity to adapt, posing a serious threat to their survival.



Reindeer have endured for over 7,000 years on the Arctic archipelago of Svalbard. Will they be able to withstand climate change?


Despite the challenges of inbreeding and limited genetic diversity, the Svalbard reindeer have remarkably adapted to harsh living conditions in an extraordinarily short period, a situation researchers term a genetic paradox. However, the question remains: can they withstand the impacts of climate change?


“Of all the subspecies of reindeer found in the high north, the Svalbard reindeer has the most inbreeding and the lowest genetic diversity,” says Nicolas Dussex, a postdoc at the Norwegian University of Science and Technology’s (NTNU) Department of Natural History.


It was only 7000-8000 years ago that the first reindeer migrated to Svalbard, most likely from Russia via Novaya Zemlya and the islands of Franz Josef Land. Perhaps there were no more than a few animals that established themselves on the Arctic archipelago. Evolutionary theory suggests this is a poor starting point since inbreeding can quickly lead to an accumulation of harmful mutations and genetic variants followed by disease and death.


But this has not prevented the Svalbard reindeer from evolving into what is today a viable population of more than 20,000 animals.

“Despite the low genetic diversity, they have managed to develop a number of adaptations to life in the High Arctic. They are, for example, smaller in size and have shorter legs than other northern reindeer and caribou subspecies,” says Dussex.

The ability to digest mosses in the absence of lichens, and to adjust their circadian rhythm to the extreme seasonal variations on Svalbard, are also traits the Svalbard reindeer have developed over the relatively short time they have lived isolated on the archipelago. 

Now, researchers at NTNU and collaborating institutions have analyzed genetic samples from 91 reindeer to see how they differ from their relatives on the mainland.  READ MORE...