TY - JOUR

T1 - Ancient DNA reveals multiple origins and migration waves of extinct Japanese brown bear lineages

AU - Segawa, Takahiro

AU - Yonezawa, Takahiro

AU - Mori, Hiroshi

AU - Akiyoshi, Ayumi

AU - Allentoft, Morten E.

AU - Kohno, Ayako

AU - Tokanai, Fuyuki

AU - Willerslev, Eske

AU - Kohno, Naoki

AU - Nishihara, Hidenori

PY - 2021

Y1 - 2021

N2 - 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.

AB - 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.

KW - ancient DNA

KW - brown bear

KW - mitochondrial genomes

KW - Pleistocene megafauna

KW - URSUS-ARCTOS

KW - GENOME SEQUENCE

KW - READ ALIGNMENT

KW - PLEISTOCENE

KW - PHYLOGEOGRAPHY

KW - MODEL

KW - PERFORMANCE

U2 - 10.1098/rsos.210518

DO - 10.1098/rsos.210518

M3 - Journal article

C2 - 34386259

VL - 8

JO - Royal Society Open Science

JF - Royal Society Open Science

SN - 2054-5703

IS - 8

M1 - 210518

ER -