The genetic differentiation and geographical pathway of Loxoblemmus appendicularis complex (Orthoptera: Gryllidae) in Taiwan based on mitochondrial 16S rDNA gene and AFLP

• Main Authors: Chen-Yu, Liu, 劉貞妤
• Other Authors: 陳明義
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/47967628201519994217

碩士 === 中興大學 === 生命科學系所 === 95 === Loxoblemmus appendicularis complex live in grassland or leaves under the woods. Taxonomic determination based on variable morphological characters and distributed area of this species complex has failed to elucidate their relationships. We collected 54 populations, 455 individuals from Taiwan, Hongkong and China, and used 16S rDNA and AFLP to clarify genetic differentiation and geographical pathway of the species complex. Sequence divergences and phylogenetic analysis reveal that six haplogroups can be identified and with average sequence divergence of 2-3.2 % among haplogroups and 0-0.9 % within haplogroup. Six haplogroup has been found to coincide with their area of geographical distribution; Haplogroup Ⅰis located in Hongkong, and Ⅲ, Ⅳ, Ⅴ, Ⅵ in western, southwestern, southern, and southeastern Taiwan, respectively; while Haplogroup Ⅱ contains only four individuals from southern Taiwan. Some haplogroups with high differentiation could be further divided into several subgroups with an average sequence divergence from 0.2 to 1.4 %. According to nested clade analysis and haplotype diversity, we found the highly diversified populations in Wulai and Miaoli County of western Taiwan, in Mudan of Pingtung County of southern Taiwan, and in Jinglun of Taitung County of southeastern Taiwan were the possible dispersal centers of Haplogroup Ⅲ, Ⅴ, and Ⅵ, respectively; genetic differentiation/gene flow and the migratory pathway of the above three haplogroups might be related to the geographical events of glaciations and the uplift of Central Mountain Range (CMR). Furthermore, according to the substitution rate of orthopterid 16S rDNA, 2-2.4 % per million years, and the calibrated points of land bridge in early Pleistocene in 180 Mya, plus the dramatic uplift of Central Mountain Range in 150 Mya, we suggest that the original populations might expand from China to Taiwan in the early Pleistocene, then retire to southern Taiwan by the following glaciations; and the retired populations were separated by CMR uplift event to Haplogroup Ⅴ and Ⅵ. Recent glaciations (20,000-110,000 years before present) obliqued the Haplogroup Ⅳ retired to southwestern Taiwan and introduced Haplogroup Ⅲ to western Taiwan.