Decrease in Effective Population Size After the Immigration of Asian Black Bears to Japan

Naoki Ohnishi, Valentin Guskov, Shuri Kato, Ririko Koido, Kentaro Uchiyama, Yoshiaki Tsuda

В журнале Ecological Research

Год: 2026 Том: 41 Выпуск: 1

The genetic structure and demographic history of the Asian black bear (Ursus thibetanus) in Japan were investigated using Double digest restriction-site associated DNA sequencing (ddRADseq). Analysis of 83 individuals revealed seven regional populations with clear geographic structure. Bayesian clustering and principal coordinate analysis showed low genetic differentiation in central populations and higher divergence in peripheral populations. The fluctuation of effective population size (Ne) inferred from SNP data showed an initial decline until around 200,000 years ago, followed by two additional reductions in most populations, with no evidence of recovery. These declines likely correspond to migration from the continent, habitat loss during the Last Glacial Maximum, and human expansion. Nuclear data suggest male-biased gene flow across mitochondrial DNA lineage boundaries. Isolated populations exhibited low heterozygosity and high genetic differentiation, emphasizing the impact of habitat fragmentation. This is the first large-scale population genomic study of Asian black bears and provides important insights for conservation and future genomic research.

DOI 10.1111/1440-1703.70029

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