Potential refugia in Taiwan revealed by the phylogeographical study of Castanopsis carlesii Hayata (Fagaceae)

Abstract

In this study, we examined spatial patterns of chloroplast DNA (cpDNA) variation in a total of 30 populations of Castanopsis carlesii Hayata (Fagaceae), a subtropical and temperate tree species, including 201 individuals sampled throughout Taiwan. By sequencing two cpDNA fragments using universal primers (the trnL intron and the trnV-trnM intergenic spacer), we found a total of 1663 bp and 21 polymorphic sites. These gave rise to a total of 28 cpDNA haplotypes. The level of differentiation among the populations studied was relatively high (GST = 0.723). Two ancestral haplotypes are widely distributed. The Central Mountain Ridge (CMR) of Taiwan represents an insurmountable barrier to the east-west gene flow of C. carlesii. Among the populations studied, three separated populations, at Lienhuachih, Fushan and Lichia, have high nucleotide diversity. Estimates of NST-GST for populations on both sides of the CMR indicate that no phylogeographical structure exists. According to the genealogical tree, number of rare haplotype and population genetic divergence, this study suggests that two potential refugia existed during the last glaciation: the first refugium was located in a region to the north of Hsuehshan Range (HR) and west of the CMR; the second refugium was located in south, especially southeastern Taiwan. In fact, the second refugium happens to be the same as that reported for Quercus glauca. A 'star-like' genealogy is characteristic when all haplotypes rapidly coalesce and is a general outcome of population expansion. The neutrality test and mismatch distribution also suggest demographic expansion recovering from a bottleneck.

Elucidating genetic signatures of native and introduced populations of the Cycad Blue, Chilades pandava to Taiwan: a threat both to Sago Palm and to native Cycas populations worldwide

“…Moreover, populations in Taiwan could indeed represent a relatively old colonization. Multiple lines of evidence suggest that southeastern Taiwan constituted a Pleistocene refuge (see examples in Cheng et al 2005 andLee et al 2006). The native hostplant, Cy.…”

“…The CMR is reported as a biogeographic boundary for other Taiwanese biota (e.g. Cheng et al 2005;Chen et al 2006;Tzeng et al 2006). Among these sites, Luye (No.…”

Does infraspecific taxonomy match species evolutionary history? A phylogeographic study of Arundo formosana (Poaceae)

“…This central mountain range has acted as a barrier for most of the 25 plant and animal taxa studied in Taiwan-wide phylogeographic evaluations (e.g. Toda et al, 1998;Wang, Hsu & Chiang, 2000;Huang, Hwang & Lin, 2002;Cheng, Hwang & Lin, 2005;Oshida et al, 2006;Wu et al, 2006aWu et al, , 2007Jang-Liaw, Lee & Chou, 2008;Kuo et al, 2014;Yu, Lin & Weng, 2014).…”

Patterns of Microbial Genetic Diversity and the Correlation Between Bacterial Demographic History and Geohistory

“…The significant negatives of both Tajima's D and Fu's Fs indices, especially the high sensitivity in population expansion of negative Fu's Fs (Fu, 1997), suggest an increase in the population size. In addition, the mismatch distribution also demonstrates a leftskewed curve with a higher difference of frequency than expected, which is commonly explained by a population growth after a bottleneck event (Hwang et al, 2003;Cheng et al, 2005;Johnson et al, 2007). However, the number of differences is lower in the observed than the expected.…”