Moscow, Russia – A recent study on the genetic history of woolly mammoths on Wrangel Island challenges previous assumptions about the animals’ demise. Researchers compared 50,000 years of genomes from mainland and isolated Wrangel Island mammoths to uncover surprising findings that shed light on the evolution of small populations and have implications for conservation efforts today.
Lead author Marianne Dehasque and her international team sequenced 21 mammoth genomes, including newly sequenced ones from Wrangel Island mammoths. The genomes spanned a wide timeframe, from a female Siberian mammoth that died over 50,000 years ago to Wrangel Island males that perished around 4,000 years ago. Through their analysis, the researchers observed a remarkable transition in population size and genetic health of the mammoths.
The study revealed that the Wrangel Island mammoth population faced a severe bottleneck, with the total number dropping to fewer than 10 individuals at one point. This led to increased inbreeding, evidenced by elevated runs of homozygosity in the genome. Despite the small population size, the mammoths managed to recover and maintain stable levels of inbreeding and genetic diversity until their extinction.
While it was previously believed that genetic defects due to inbreeding led to the mammoths’ extinction, the research showed a more complex story. The isolated population faced challenges such as inbreeding depression and purging harmful mutations, which prolonged the evolutionary process. The prolonged purging of harmful mutations indicated long-lasting negative effects on the population until their eventual extinction.
The findings not only provide insights into the genetic history of Wrangel Island mammoths but also have broader implications for conservation biology. The study highlights the importance of genetic diversity and the impact of isolation on small populations, offering valuable lessons for modern conservation efforts. Researchers hope that by understanding the challenges faced by past populations, we can better protect and preserve endangered species today.