Researchers have now sequenced the genome of the woolly mammoth and have concluded that the last members of the species probably died on an isolated island, where inbreeding may have led to a population too small to be sustainable.

The scientists used DNA from two specimens, the 45,000-year-old soft tissue remains of a woolly mammoth found in northeastern Siberia, and a 4,300-year-old tooth from one found on Wrangel Island, a Russian territory in the Arctic Ocean that was separated from the mainland by rising sea levels about 12,000 years ago.

Researchers were able to sequence the complete genomes of these two well-preserved specimens. By measuring the amount of genetic diversity in each, they were able to draw some conclusions about the mammoth’s history and extinction.

About 300,000 years ago, the population of woolly mammoths suddenly declined; it took more than 100,000 years to recover.