DNA from mammoth remains reveals history of last surviving population

Enlarge / A artists design of A of THE last mammoths of Wrangel Island. Beth Zaiken

A little band of woolly mammoths became trap on Wrangel Island around 10,000 years There is When rising sea levels separated THE island Since continent Siberia. Little, isolated populations of animals lead has inbreeding And genetic defaults, And he has long has been thought that THE Wrangel Island mammoths Ultimately succumbed has This issue about 4,000 years there is.

A paper In Cell on THURSDAY, However, compared with 50,000 years of genomes Since continent And isolated Wrangel Island mammoths And find that This was not THE case. What THE authors of THE paper discovered not only challenges OUR understanding of This isolated band of mammoths And THE evolution of little populations, he Also has important consequences For conservation efforts today.

A severe neck

It is THE culmination of years of genetic sequencing by members of THE international team behind This new paper. They studied 21 mammoth genomes—13 of which were newly sequence by lead author Marianne Dehasque; others had has been sequence years Before by co-authors Patricia Pečnerová, Foteini Kanellidou, And Heloise Muller. THE genomes were got Since Siberian woolly mammoths (Mammuthus primigen), both Since THE continent And THE island Before And After he became isolated. THE the oldest genome was Since A female Siberian mammoth WHO deceased about 52,300 years There is. THE the youngest were Since Wrangel Island male mammoths WHO perished RIGHT around THE time THE last of these mammoths deceased out (A of them deceased just 4,333 years there is).

Enlarge / Wrangel Island, north of Siberia has A extensive tundra. Love Dalen

It is A outstanding And developer time scope: THE sample included mammoths Since A population that begin out big And genetically in good health, went through isolation, And Ultimately went disappeared.

Mammoths, THE team note In their paper, experimented A “climatically turbulent period," particularly during A episode of fast warming up called THE Bølling-Allerød interstadial (approximately 14,700 has 12,900 years there is a time that others to have suggested could to have directed has local woolly mammoth extinctions. However, THE genomes of mammoths studied through This time period don't do it indicate that THE warming up had any of them negative effects.

Negative effects only appeared - and radically so—once THE population was isolated on that island.

THE the team simulation indicate that, has It is the smallest, THE total population of Wrangel Island mammoths was less that ten people. This represented A severe population neck. This was seen genetically through increase short of homozygosity In THE genome, cause When both parents contribute almost identical chromosomes, both derivative Since A recent ancestor. THE short of homozygosity In isolated Wrangel Island mammoths were four times as great as those Before sea levels pink.

Despite that dangerously tiny number of mammoths, they restored. THE population size, as GOOD as inbreeding level And genetic diversity, stayed stable For THE following 6,000 years until their extinction. Contrary to THE initial population neck, genomics signature on time seem has indicate inbreeding Ultimately offbeat has pairings of more far parents, suggesting either A bigger mammoth population Or A change In behavior.

In 20 generations, their simulation indicate, THE population size would be to have increase has about 200-300 mammoths. This East consistent with ...