Genetic Structure Of Chinese Mainland Mitten Crabs Inferred From Mitochondrial DNA Markers

This thesis includes three chapters:Chapter 1: The summarization of molecular phylogeography and researches on crabs and shrimps.Chapter 2: This study used complete mitochondrial cyt b gene sequences to explore genetic structure of Chinese Mainland mitten crabs. A total of 35 haplotypes were defined by sequences variance and SSCP in 239 individuals collected from 13 locations in eight populations. Phylogenetic trees (ML and Baysian) revealed two distinct clades, sinensis clade and hepuensis clade. Clades of haplotypes from Liaohe, Yalujiang and Oujiang were nested within clade of Changjiang for their close relationship both in ML and Baysian trees, which implied mitten crabs of the three rivers rooted in Changjiang river. Oujiang and Qingnianhe rivers were the high zones of Eriocheir japonica hepuensis and E. j. sinensis by hybrid degree and genetic diversity; Direction of gene flow between north populations was from north to south, but south populations from south to north. Mismatch distribution of pairwise differences and Tajima's D and Fu's test showed a relatively more complex population history or population genetic structure. MSN revealed each subspecies had own ancestral haplotypes forming a "star-like" shape. Chuzhou and Nanjing to Maanshan with high genetic diversity should be protected to conserve wild resource of Chinese mitten crabs.Chapter 3: Structure and sequence variance of the mitochondrial control region in mitten crabs. Control region was divided into two domains: variable domain and tandem repeat sequences. TA repeat was in both E. j. hepuensis and E. j. sinensis, another repeat unit in E. j. hepuensis was C(TA)₃; but G(TA)₂TG(TA)₃T, G(TA)₁TG(TA)₅T, G(TA)₁TG(TA)₆T, G(TA)₂T, G(TA)₄T, G(TA)₅T and G(TA)₆T in...