2017-03-02. The Woolly Mammoth’s Last Stand.

posted Mar 7, 2017, 9:04 AM by Alan Gould   [ updated Mar 7, 2017, 5:07 PM ]
By Nicholas Wade, The New York Times. For GSS Losing Biodiversity chapter 4. Excerpt: In a remote, mist-wrapped island north of the eastern tip of Siberia, a small group of woolly mammoths became the last survivors of their once thriving species. They fell extinct 4,000 years ago, having endured for some 6,000 years after the mammoths of the mainland had died off. From a message left in the tooth of a male mammoth, geneticists have now deciphered the probable reason for the population’s demise. The story is relevant to living populations of endangered species, because it supports the idea that as a population dwindles, natural selection becomes less efficient at purging bad mutations, leading to loss of genes and a slow meltdown of the genome. The implication is that once numbers fall below a certain level, genetic decline is irreversible....  https://www.nytimes.com/2017/03/02/science/woolly-mammoth-extinct-genetics.html

See also: UC Berkeley News article  - Woolly mammoths experienced a genomic meltdown just before extinction.