Mammoths of Wrangel Island: A tale of survival and sudden extinction
10,000 years ago, on Wrangel Island, off the coast of Siberia, a unique population of mammoths began to emerge. Scientists published their findings in the journal "Cell," speculating how these mammoths became extinct.
Scientists from the international research team discovered that a small group, possibly no more than eight mammoths, became separated from the mainland due to rising sea levels. As a result, these mammoths survived on this isolated island for the next several thousand years.
Data analysis shows that over approximately 20 generations, the mammoth population on Wrangel Island grew to about 200-300 individuals. However, DNA studies indicated that inbreeding occurred, leading to low genetic diversity.
Still, scientists believe that genetic factors may not have caused their extinction. "We can definitively dismiss the notion that the population was doomed to extinction due to genetic reasons," explains Love Dalén, an evolutionary geneticist from the University of Stockholm and co-author of the publication.
Dalén adds that the probable cause of the mammoths' extinction on Wrangel Island was an unforeseen event. Had this event not occurred, the mammoths might still live there today.
The research team conducted a genomic analysis of 21 woolly mammoths—14 from Wrangel Island and seven from the continental population. The samples covered the last 50,000 years of these animals' existence.
Compared to their continental ancestors, the genomes of Wrangel Island mammoths exhibited signs of inbreeding and low genetic diversity. The studies also revealed decreased diversity in a group of genes that plays a crucial role in the immune response.
The genetic diversity of the island's population declined over six thousand years, but this process was gradual. This suggests that the population size remained stable until its eventual extinction.
