Ancient DNA reveals multiple origins and migration waves of extinct Japanese brown bear lineages.


Type
Article
Change log
Authors
Yonezawa, Takahiro 
Mori, Hiroshi 
Akiyoshi, Ayumi 
Allentoft, Morten E 
Abstract

Little is known about how mammalian biogeography on islands was affected by sea-level fluctuations. In the Japanese Archipelago, brown bears (Ursus arctos) currently inhabit only Hokkaido, the northern island, but Pleistocene fossils indicate a past distribution throughout Honshu, Japan's largest island. However, the difficulty of recovering ancient DNA from fossils in temperate East Asia has limited our understanding of their evolutionary history. Here, we analysed mitochondrial DNA from a 32 500-year-old brown bear fossil from Honshu. Our results show that this individual belonged to a previously unknown lineage that split approximately 160 Ka from its sister lineage, the southern Hokkaido clade. This divergence time and fossil record suggest that brown bears migrated from the Eurasian continent to Honshu at least twice; the first population was an early-diverging lineage (greater than 340 Ka), and the second migrated via Hokkaido after approximately 160 Ka, during the ice age. Thus, glacial-age sea-level falls might have facilitated migrations of large mammals more frequently than previously thought, which may have had a substantial impact on ecosystem dynamics in these isolated islands.

Description
Keywords
Pleistocene megafauna, ancient DNA, brown bear, mitochondrial genomes
Journal Title
R Soc Open Sci
Conference Name
Journal ISSN
2054-5703
2054-5703
Volume Title
8
Publisher
The Royal Society
Sponsorship
Wellcome Trust (214300/Z/18/Z)