Phylogeography of the component species of broad-leaved evergreen forests in Japan, based on chloroplast DNA variation

Abstract

In order to elucidate the past distribution and colonization routes of broad-leaved evergreen (lucidophyllous) forests, we investigated the intraspecific phylogeographic patterns of lucidophyllous forests in Japan and surrounding areas. We selected 6 component species with a similar geographic distributions growing in Castanopsis-dominant forests. We defined possible important refugia during the glacial periods as the regions rich in rare haplotypes (with a frequency of 5% or less), or as regions rich in the number of common haplotypes (with a frequency of more than 5%). We then located the sites of refuge by comparing the intraspecific phylogeographic patterns among 6 component species of lucidophyllous forests with respect to these two parameters (i.e., haplotype uniqueness and the number of haplotypes). The following results were obtained during the course of this study: (1) rare haplotypes were distributed among islands around the main islands of Japan; (2) rare subtypes and the greatest numbers of common haplotypes were observed in Kyushu, a finding which agreed with fossilized pollen data demonstrative of the past existence of refugia in southern Kyushu; and (3) rare haplotypes were found on the Muroto Peninsula, and the second greatest numbers of common haplotypes were observed on the Kii Peninsula, a finding which suggested the existence of additional important refugia along the Pacific coast of Japan during the glacial ages.

Intraspecific Phylogenetic Relationships of Caryopteris incana in the Tsushima Islands, Japan, Using DNA Sequence Analysis

“…The field focuses, in particular, on genetic variation in phylogeography, and has been used to examine various species worldwide in order to clarify the evolutionary history of organisms that have survived the glacial and interglacial periods over the past tens of thousands to millions of years [2]- [5]. The islands of Japan, located in East Asia, are a hotspot for immigration to, and emigration from, continental Asia, and, similar to the Mediterranean region, there has been repeated connection and fragmentation of lands over glacial and interglacial periods [6]- [8].…”

Genetic variation of Ginkgo biloba L. (Ginkgoaceae) based on cpDNA PCR-RFLPs: inference of glacial refugia

“…In contrast to intense investigations on plants of Europe and northern America (Hewitt, 2000;Shen et al, 2002), understanding of the effects of past climatic events on population structure and phylogeny of species in Asia is relatively limited (Szmidt and Wang, 1993;Wang and Szmidt, 1994;Szmidt et al, 1996;Chen et al, 1997;Tomaru et al, 1997;Lin, 2001;Huang et al, 2002;Lu et al, 2002;Okaura and Harada, 2002;Aoki et al, 2004). The Eurasian ice sheets covered millions of square kilometers of the continent in the late Pleistocene period (Svendsen et al, 1999).…”

Distribution and Phylogeography of <i>Caryopteris incana</i> (Lamiaceae) Based on Chloroplast DNA Sequences in West Kyushu, Japan

“…Because these classifications indicated a similar result within the family tree, we speculated that the common ancestor of C. incana in Japan diverged into two groups near center part of haplotype network. Several phylogeographical studies in these areas had suggested a southward transfer during the LGM, followed by a northward transfer during the period of de-glaciation [28] [29]. From this, it was suggested that C. incana transferred southward from the Korean Peninsula to the Goto Islands and the Nagasaki Mainland, with the decrease in temperature during the glacial period, followed by an expansion northward or southward to each area.…”