Cytoplasmic DNA variation and biogeography of Larix Mill. in Northeast Asia

Range-wide variation in 54 populations of Dahurian larch (Larix gmelinii) and related taxa in Northeast Asia was assessed with four mitochondrial PCR-RFLP and five chloroplast SSR markers. Eleven mitotypes and 115 chlorotypes were detected. The highest diversity was observed in the southern Russian Far East where hybrids of L. gmelinii, L. olgensis and L. kamtschatica are distributed. In contrast, only two mitotypes occurred in L. cajanderi and L. gmelinii. The Japanese larch (L. kaempferi) was found to be closely related to populations of L. kamtschatika inhabiting the Kuril Islands and South Sakhalin, populations from the northern part of Sakhalin being more closely related to continental species. In general, both mitochondrial (GST = 0.786; NST = 0.823) and chloroplast (GST = 0.144; RST = 0.432) markers showed a strong phylogeographical structure and evidence of isolation-by-distance. Yet both markers did not allow a clear delineation of species borders. In particular, and contrary t...