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Based on fossil pollen, the distribution range of Taiwan fir [Abies kawakamii (Hay.) Ito] (Pinaceae) is smaller than it was 50 000 years ago. To characterize the present refuge populations of A. kawakamii, which survive only in subalpine forests in Taiwan, we surveyed nuclear genes and chloroplast intergenic spacers to assess the genetic diversity of Taiwan fir. Populations maintain high genetic diversity and contain similar numbers of haplotypes for the GapC (cytosolic glyceraldehyde 3-phosphate dehydrogenase) fragment. Haplotypes for GapC are generally widespread, and population-specific haplotypes accounted for 2.5% of the total. Differentiation among populations is very low (GST = 0.01). Only three haplotypes were detected for the cpDNA marker, and every population had one or two haplotypes. In a neutrality test, the variation in nucleotides did not deviate from that expected with neutral evolution for either marker. A retreat route to higher elevations was not evident from either the GapC or cpDNA markers. Hsuehshan was the site of the most divergent population in Taiwan. We concluded that uniform genetic diversity, low differentiation, low numbers of population-specific haplotypes, and neutral evolution characterize contemporary refuge populations of Taiwan fir. [ABSTRACT FROM AUTHOR]

Aim The purpose of this paper was to study the patterns of genetic variation, demographic history, haplotype relationships and potential location of diversity centres of two closely related species, Machilus thunbergii and Machilus kusanoi. Location The phylogeography of M. thunbergii and M. kusanoi was examined by sampling 110 and 106 individuals from 25 and 16 sampling sites, respectively, across their distributional range in Taiwan. Machilus thunbergii is distributed on the Asian mainland, South Korea, southern Japan, the Ryukyus, Taiwan and the Philippines, whereas M. kusanoi is endemic to Taiwan. These two species are closely related, and both are widely distributed in Taiwan but occupy different altitudinal zones and habitats. Methods The range-wide variation of M. thunbergii and M. kusanoi in Taiwan was studied using chloroplast DNA (cpDNA) variations. A haplotype network was constructed with the computer programtcs. Nested clade analysis was conducted with the computer programceodis, and various parameters of genetic diversity were calculated and neutrality tested by the computer program DnaSP. Population differentiation was estimated using the programsarlequin andhapstep. The contribution of the populations to gene diversity and to allelic richness was calculated using the softwarecontrib. The level of divergence for each population from the remaining populations was calculated as the mean value of pairwise FST for each population against the rest of the populations. Results Extremely low levels of genetic differentiation were found for both species. This result suggested that these two species probably survived in multiple relict refugia with different population sizes throughout the island during low-temperature periods of the Pleistocene. In addition, nested clade analysis (NCA) of cpDNA haplotypes indicated that restricted gene flow with isolation-by-distance characterized the recolonization after the Pleistocene by Tashueshan and Shiouhluan populations of M. thunbergii in the north-central area west of the Central Mountain Range (CMR). In contrast, NCA analysis indicated that a major diversity centre on the southern tip of the island (Kending population) and contiguous range expansion characterized the recolonization by M. kusanoi of northern areas along the east side of the CMR. The major diversity centres found for the two species examined were further supported by the results of the mean FST for individual populations in comparison with other populations, and of the contribution of the divergence component to the total diversity. Main conclusions This research supports the multiple relict refugia hypothesis for both species investigated. Populations of M. thunbergii at Shiouhluan and Tashueshan in the north-central area west of the CMR represent a diversity centre currently expanding its size. A diversity centre at the southern-edge population of M. kusanoi, and a contiguous range expansion from Kending, were found. These results indicate that the M. thunbergii populations at Tashueshan and Shiouhluan and the M. kusanoi population at Kending, and even Soukar, are evolutionarily significant units for conservation programmes. [ABSTRACT FROM AUTHOR]

In this study, we examined spatial patterns of chloroplast DNA (cpDNA) variation in a total of 30 populations ofCastanopsis carlesiiHayata (Fagaceae), a subtropical and temperate tree species, including 201 individuals sampled throughout Taiwan. By sequencing two cpDNA fragments using universal primers (thetrnL intron and thetrnV-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 ofC. carlesii. Among the populations studied, three separated populations, at Lienhuachih, Fushan and Lichia, have high nucleotide diversity. Estimates ofNST– 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 forQuercus 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. [ABSTRACT FROM AUTHOR]

This paper described current phylogeographical patterns of chloroplastic DNA variation of Trochodendron aralioides, a temperate tree species, and inferred its possible refugium in Taiwan. This information was compared with the known phylogeographical pattern of subtropical tree species. A total of 24 populations were sampled including 20 from Taiwan, two each from the Ryukyus and Japan. A haplotype network was constructed by computer program TCS, various parameters of genetic diversity were calculated and neutrality was tested by computer program DnaSP. To examine the similarity of genetic structure among populations, a maximum parsimony tree was reconstructed by computer program PAUP*. The results of isozyme of T. aralioides from a previous publication were incorporated into this study to infer the phylogeographical history. Nine haplotypes according to six substitutions, two indels and one inversion of the two cpDNA intergenic spacer fragments ( petG- trnP and petA- psbJ) of T. aralioides were recognized. Genetic structure of the population of Japan is totally different from those of Taiwan and the Ryukyus. In Taiwan, the genetic structure was differentiated among populations revealed by Gst = 0.700 and Nst = 0.542, and the population genetics was clearly spatially structured. Two population groups were recognized. The first group was distributed islandwide and extended to the Ryukyus. The second group contained five of the seven known haplotypes, and was restricted to the area between latitude 24°46′ and 24°06′ N. In Taiwan, north-central area between latitude 24°46′ and 24°06′ N is potentially a refugium during the last glaciations. This finding is contradicted to subtropical species as Cyclobalanopsis glauca. [ABSTRACT FROM AUTHOR]

Abstract Phylogeographical and mismatch analysis of chloroplast DNA (cpDNA) variation were used to infer the temporal dynamics of distributional and demographic history of Taiwan fir (Cunninghamia konishii ). We examined 64 and 52 trees from 17 populations of C. konishii and 14 provenances of C. lanceolata , respectively, by sequencing three intergenic spacers and one intron using cpDNA universal primers. Of the aligned 1888 base pairs (bp) sequence, 30 varied among 28 haplotypes, which consisted of three transitions, 14 transversions and 13 indels. One ancestral haplotype was found in 86 individuals across the surveyed range of both species, C. konishii and C. lanceolata , which was distributed in all populations and provenances. The 28 haplotypes also included 15 C. konishii specific and 12 C. lanceolata -specific haplotypes. Ancestral haplotype was found fixed in five populations of C. konishii and five provenances of C. lanceolata . Other haplotypes occurred mainly as singletons. The levels of population differentiation studied are relatively low in both Cunninghamia species. The nucleotide diversity (θ ) of chloroplast DNA sequences within C. konishii was slightly higher than that of C. lanceolata . Excess in singletons as well as star-like phylogeny of haplotypes suggested no clearcut migration patterns of C. konishii after glacial maximum. One probable demographic history of C. konishii is the postglacial population growth of C. konishii after a glacial bottleneck event. This inference is supported by the combined results of fossil pollen record, low nucleotide diversity, significant Tajima's d -value, phylogeographical analysis and unimodal mismatch distribution. Similarities and discrepancies between our results and those of Lu et al. (2001) are discussed. [ABSTRACT FROM AUTHOR]