Inbreeding didn't kill off Wrangel mammoths
13 Apr 2012 by Evoluted New Media
Mammoths living on Wrangel Island didn’t go extinct due to inbreeding says new research.
The majority of mammoths disappeared from Eurasia and North American 10,000 years ago, but a small population of mammoths managed to survive on Wrangel Island for another 6,000 years. It was thought they went extinct because inbreeding led to a loss of genetic diversity, but new research has found otherwise.
Using a novel approach to analyse ancient genetic variation – and doing so on a large number of mammoth remains – an international research team were able to track temporal changes in genetic diversity in great detail. The team – which included academics from Royal Holloway University of London – found the Wrangel mammoths were in good genetic health up until they finally became extinct.
“We discovered that about half of the genetic variation was lost at the end of the last Ice Age, some 10,000 years ago,” said lead author Dr Veronica Nyström. “However, we found no further loss in variation during the ensuing 6,000 years when mammoths were isolated on Wrangel Island.”
It has been suggested that the mammoth population – thought to be around 500 individuals – was large enough to maintain genetic diversity and avoid inbreeding. The effective population size – roughly equal to the number of reproducing individuals in a population – is a measure that geneticists use to examine how populations are affected by evolutionary processes.
“What’s really interesting is that maintaining 500 effective individuals is a very common target in conservation programs,” said Dr Love Dalén from the Swedish Museum of Natural History. “Our results therefore support the idea that such an effective population size is enough to maintain genetic diversity for thousands of years.”
The research has been published in Molecular Ecology.
