Nagamitsu T., Barkalov V.Yu., Uchiyama K., Sugai K., Otsu C., Shitara T.
Plant Species Biology 2025; 40(5): 439-451
Betula davurica Pallas is widely distributed in continental regions of northeast Asia but is disjunctly distributed in the Japanese Archipelago. To examine the lower diversity and higher differentiation in genetic and phenotypic variations expected in these disjunct populations compared to the continental populations, genome-wide single-nucleotide polymorphism (SNP) genotypes, chloroplast (cp) DNA sequences, and leaf morphology were investigated in seven disjunct populations in Hokkaido and Honshu in comparison to three populations in Primorye, where B. davurica is continuously distributed. SNP genotypes of putative octaploid individuals indicated that genetic diversity was higher in Honshu (0.158 ≤ HE ≤0.176) than in Hokkaido and Primorye (0.145 ≤ HE ≤0.149). Genetic differentiation between Honshu and the other regions (0.011 ≤ FST ≤0.035) was larger than that between Hokkaido and Primorye (0.002 ≤ FST ≤0.009) and within regions (0.001 ≤ FST <0.007)...
