Intraspecific Sequence Variation of Chloroplast DNA Reflecting Variety and Geographical Distribution of Polygonum cuspidatum (Polygonaceae) in Japan

Abstract

in Japan, we analyzed the chloroplast DNA sequences of a region from the rbcL to the accD gene (ca. 1,420 bp), and found nucleotide variations at 22 sites in 68 samples. The phylogenetic relationship deduced from the sequence variations revealed the existence of at least five groups. The first group consisted of P. cuspidatum var. cuspidatum in the central part of Honshu; in Nagano, Yamanashi, and Shizuoka. The second, a sister of the first, consisted of those plants in Shizuoka-Itoigawa Line. The third group consisted of plants in the northern part of Japan including P. sachalinense in Hokkaido, P. cuspidatum var. cuspidatum in Aomori and var. uzensis in Akita. The fourth consisted of var. uzensis in the Tohoku District. The fifth consisted of var. terminalis in the Izu Islands. P. cuspidatum are differentiated according to their distribution, and two varieties, var. terminalis and var. uzensis, are differentiated genetically. Polygonum sachalinensis, a distinct species morphologically, fell into the accessions of P. cuspidatum on the phylogenetic tree obtained in the present study.