Dissertation > Biological Sciences > Zoology > Animal evolution and development

Qinling Asian venomous snake phylogeny and geographical evolution

Author LiXiaoPeng
Tutor LiangGang
School Shaanxi Normal University
Course Developmental Biology
Keywords Qinling Asian genus Agkistrodon Cytochrome b gene NADH dehydrogenase subunit IV Phylogenetic Geographic evolution
CLC Q951
Type Master's thesis
Year 2009
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Asian venomous snake genus (Gloydius) is the most widely distributed in China, the largest number of a class of snakes, their wide distribution range of habitats vary widely, from snow-capped mountains, plateaus, hills to the plains, is a highly differentiated, groups adapt to a variety of environmental conditions . Although China viper is rich in resources, but for the genetic diversity of the species and their geographical distribution pattern currently poorly understood. Paper were on the mitochondrial DNA cytochrome b gene (Cytb) and NADH dehydrogenase subunit 4 (ND4) gene as a molecular marker, Qishan, Shaanxi Province, Yang County, Ningshan, Hanyin and Anhui Huangshan five different geographical populations of short-tailed venomous snake (G.brevicaudus) and Shaanxi baota of intermedius (G.intermedius), Taibai Qinling venomous snake (G.qinlingensis) and Bai and NINGSHAN two different geographic populations jerdonii (Trimeresurus jerdonii ) Cytb and ND4 genes were sequenced genes of these two kinds of gene sequence analysis and comparison as molecular markers, genetic data were constructed single and joint genetic data ML, NJ, MP and Bayesian trees, Based on this, combined with the geographical distribution of the Qinling region viper and morphological characteristics of the distribution of Shaanxi Province phylogenetic relationships viper, viper Qinling geographic distribution pattern and evolution reasons are discussed, aimed at distributed in Shaanxi Province Asia venomous snakes are the genetic relationship between the Qinling region viper distribution patterns, causes and evolution of geographical evolution to provide basic information. The main results and conclusions are as follows: 1.Cytb (1067bp) and ND4 (819bp) gene sequence variation sites were 259 and 182, parsimony informative sites for the 135 and 144, conserved sites for the 808 and 637 months. In the obtained 38 gene sequences (including the outgroup) in, Cytb gene sequences have 19 (10 haplotypes), T, C, A, G, the average content of 28.3%, 11.3%, 28.1%, 32.2 %; ND4 gene 19 (11 haplotypes), T, C, A, G, the average content of 32.9%, 12.5%, 24.8%, 29.8%. AT content of the sequence of two genes (56.4%, 57.7%) were significantly higher than that of GC content (43.5%, 42.5%) as a sequence of a typical of a high AT content. 2 Based on Cytb, ND4, Cytb and ND4 data sets were constructed jointly the four phylogenetic tree shows that different geographic populations tailed venomous snake clustering relationship is entirely consistent. ND4 constructed in the four phylogenetic tree constructed and Bayesian Cytb tree, different geographic populations tailed venomous snake with Shaanxi Qinling Taibai County Tsui town together into a large venomous snake first branch, and then with Shaanxi baota Yaojia slope The intermedius common aggregated. In Cytb the NJ tree, MP and ML trees, as well as joint data collection Cytb and ND4 constructed four kinds of phylogenetic tree, Qinling Mountains in Shaanxi Taibai Tsui town of venomous snake with baota Yao slope intermedius clustered into one big sticks Finally macaque populations with different geographical common venomous snake together. 3 pairs of Cytb and ND4 gene sequences transition / transversion ratio (R value) analysis showed, R values ??were significantly greater than the critical value of 2,2 kinds of gene sequence variations did not reach saturation, indicating that they are subject to evolutionary effects of noise smaller, more suitable for phylogenetic tree reconstruction. Composition for gene sequence analysis showed that two genes in Viperidae snakes exist in both intraspecific variation can be used as case studies in Asia venomous snakes in the geographical distribution of marker genes. 4 Through the comparison of two genes, Cytb gene ND4 gene than conservative, evolutionary rate is lower, for the reconstruction Asian genus Agkistrodon snake phylogeny speaking, ND4 gene significantly better than Cytb genes. ND4 gene in the Asian species of the genus Agkistrodon significantly greater than the genetic distance between intraspecific genetic distance, Cytb gene in the Asian genus Agkistrodon snake species branching structure and clustering relations have not ND4 stability. Therefore, ND4 gene Cytb genes are more than suitable for determining phylogenetic relationships among species. 5 By Cytb and ND4 gene sequence analysis and phylogenetic relationships between clusters conclusion, combined with the geographical distribution, morphological characteristics and other aspects of comprehensive analysis that the Qinling Mountains and the short-tailed venomous snake venomous snake close genetic relationship between, and and intermedius between distantly related. 6 Qinling tailed venomous snake geographical distribution pattern was clearly divided into two populations: one population is distributed in the Qinling Mountains (eg, Wu Zhang Qishan plateau) short-tailed venomous snake, and the other populations are distributed in southern slope of Qinling (eg, Ningshan County cylinder cars Bay, Yang County Huayang and Hanyin Chengguan town) short-tailed venomous snake. 7 on the short-tailed venomous snake venomous snake and Qinling geographic distribution, morphological and molecular phylogenetic relationships comprehensive analysis that the Qinling tailed venomous snake from a venomous snake gradually evolved, it was adapted to the high altitudes ecological alternative kind of life.

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