A genetic study of woolly mammoths found on an isolated Arctic island has shown that the mammals had a stable population for thousands of years, meaning they were wiped out by a random event rather than inbreeding. If it weren’t for bad luck, there would be woolly mammoths on Earth.
About 10,000 years ago, a handful of woolly mammoths found themselves isolated on an island in the Russian Arctic, off the coast of Siberia.
Over the next thousands of years, this small herd, which may have consisted of only eight individuals, grew to a stable population of 100,000 individuals. 200 to 300 mammothsBefore it became extinct about 4,000 years ago.
They were the last known inhabitants. Of these woolly mammals on Earth – and, If not unfortunatelyIt is possible that they survived into the modern era.
We know the history of these mammoths thanks to the genetic study conducted by them Love Dalinfrom Stockholm University in Sweden, and colleagues, which was presented at a condition Published this Thursday in the magazine cell.
The team examined the DNA of 14 mammoths on Wrangel Island, in addition to 7 from a group that existed on the mainland before the organisms appeared. A small group has been isolated. By rising sea levels due to the melting of ice sheets, covering a total of 50,000 years of genetic history.
The researchers’ analysis shows that despite the small number of individuals, And kinship was not the reason From the disappearance of the mammoths. According to Dalen, the population was able to eliminate major harmful genetic mutations, Although the smaller ones pile up.
“We can show that, in all likelihood, inbreeding and genetic diseases did not cause the gradual decline of the population to extinction,” the researcher says. new world. “The residents were doing wellDespite the kinship.
However, the team found that individual mammoths were affected. Genetic diseases This negative impact at the individual level continues For thousands of years.
“This means that Currently threatened specieswhich in most cases suffered from Choking very recently“They may continue to suffer from genetic diseases hundreds of generations into the future,” Dalin says.
Dallin points out Tasmanian devil As another example of a species isolated on a large island after the mainland population became extinct and now suffering from reduced genetic diversity.
This in turn, Affects the immune systemWhen this is reduced, the population is likely to decline when encountering new pathogens, e.g Facial tumor disease Which affects the demons.
“Looks like Natural selection has been effective in eliminating mutations. Potentially fatal, but And other less dangerous ones accumulated Gradually,” he says. Adrian Listerfrom the Natural History Museum, London.
“It is uncertain whether this contributed to the eventual extinction, but it may have been In association with environmental changes“There are lessons here for monitoring the genetic health of endangered species today,” Lester says.
It is not known exactly what drove the mammoths to extinction, but interestingly the availability of freshwater lakes and rivers in Wrangel suggests that they could have had They survived longer than they did.In contrast, an equally isolated group became extinct 5,600 years ago due to drought.
“All of these things, like disease, short-term weather events, tundra fires, are things we take into account Random events“It’s a very good idea,” Dalin says.
Since it is random, There was nothing inevitable If that hadn’t happened, the mammoths might still be alive in Wrangell today, assuming humans hadn’t killed them when they finally arrived.
