For a long time The twilight of the kaamos prevails in winter in the middle of the Arctic Ocean in the Svalbards, to which conditions its own deer population has adapted.
The islands' small-sized deer die in winter for lack of better moss and lose about a quarter of their weight.
Readjustment it went well, even though such a small herd of deer migrated to populate the islands after the Ice Age that its descendants should suffer from mating between too close relatives.
The long journey across the sea ice isolated the newcomers from the deer of their original home, i.e. northern Russia.
The smallness of the initial population left the genetic spectrum narrow, i.e. a genetic bottleneck was formed.
This still did not accumulate harmful genes in the deer. On the contrary, thanks to the bottleneck, they have been eliminated, an international group of researchers found.
Svalbard's deer have fewer very harmful gene variants than any other northern deer population, says the research report in the journal iScience.
The comparative populations of Russia, Norway, Greenland and Canada are all larger and have not passed through similar bottlenecks.
Result may surprise you, because people wisely avoid having children with their close relatives.
The offspring would be at risk of becoming seriously ill. He could get a double of a genetic defect that runs in the family, which would have been harmless if he had received an intact gene alongside it from the other parent.
That kind of risk really haunted the deer in Vipupuori at first. Over time, however, their population was benefited by another phenomenon that can result from frequent mating of close relatives.
The most dangerous genetic defects gradually disappeared completely, because those who suffered from them became so ill that they could no longer have offspring.
A similar elimination of harmful gene versions from a shrinking population has also previously been observed in, for example, the Indian tiger and the New Zealand kakapo, or owl parrot.
The peaks however, the deer's luck will change in the near future, researchers fear.
When they adapted to the arctic conditions during their bottleneck period, they probably specialized too much. It is difficult for them to get used to the current rate of warming in time.
Published in Science in Nature 8/2023.
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