Genetic Structure of Remnant <i>Quercus serrata </i>Populations at the Northernmost Limit of their Distribution in Japan
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The northernmost limit of distribution of <i>Quercus serrata </i>is on Hokkaido, where fragmented populations occur from the southwestern foothills of the Hidaka Mountains to the Ishikari Plain with an additional isolated population on the Oshima Peninsula. These northern marginal populations are considered to be the result of past vegetational shifts, but the genetic relationships are not fully understood. In this study, we used 11 nuclear SSR loci to genotype 667 individuals from 11 populations of <i>Q. serrata </i>in Hokkaido and six populations from the Tohoku region of Honshu. Total genetic diversity in Hokkaido (<I>H<sub>E</sub> </I>= 0.693) did not differ from Tohoku (<I>H<sub>E</sub> </I>= 0.669). The population differentiation in Hokkaido (<I>G' <sub>ST</sub> </I>= 0.097) was not significantly different from that of Tohoku (<I>G' <sub>ST</sub> </I>= 0.090). The STRUCTURE analysis distinguished four regional clusters of <i>Q. serrata</i>; the Pacific side of Tohoku, the Japan Sea side of Tohoku, the northernmost region, and the Oshima Peninsula. The findings indicate two ancestral origins from the Pacific and Japan Sea coasts of Tohoku in the Hidaka region. The results from principal coordinate analyses indicated that the isolated population on the Oshima Peninsula is more related to the populations on Hokkaido than to the Tohoku populations.
- Acta phytotaxonomica et geobotanica
Acta phytotaxonomica et geobotanica 68(1), 1-15, 2017
The Japanese Society for Plant Systematics