Genetic Structure And Geographic Phylogeography Of Phasianus Colchicus In Northern China

As a global distributional bird,the Common pheasant,Phasianus colchicus is widely distributed in Europe eastward to Kamchatka and southern Japan;In eastern Asia from eastern Siberia(52°30′N)southward to indo-China and Burma(22°N);In central Asia southward to Afghanistan,Pamir and Asia Minor(Hill and Robertson,1988).The species has been introduced in north America,western Europe and other regions (Delacour,1977;Long,1981;Johnsgard,1986).They play an important role in the ecosystem and creates lots of economic values each year in Euramerican countries.They lived through out of China except Qiangtang Plateau and Hainan province currently (Zheng,1978),with eighteen(Liu and Zhou,1985)or nineteen(Delacour,1951;Zheng, 1978)subspecies.In this thesis,Polymerase chain reaction(PCR)and dideoxy direct sequencing methods were used to analyze the genetic variance of P.colchicus in northern China from sixteen different populations:XN population,DT population,GD population, MX population,ZHX population,CHX population,JN population,ZJC population,WW population,HD population,NISH population,NSH population,SICH population,DB population,NM population and SHCH population.A total of 819 nucleotides of DNA Cyt b genes were sequenced in 154 samples to analysis the genetic structure and geographic phylogeography of P.colchicus in northern China.By comparing the mtDNA Cyt b genes(819bp)in 154 individuals from sixteen populations,we found twenty-five polymorphic sites(3.05%of the entire sequence), which defined twenty-one haplotypes(13.64%of all the samples),without insertion or deletion.There were significant Codon Bias Index(CBI)at the third locus,and the value was 0.58.Among the twenty-one haplotypes,Hap-1 exists in uniquity,68.2%of total samples.In the parsimony network,Hap-1 was the root haplotype in all of haplotypes, from which we suggested that Hap-1 was the ancestral haplotype.All the populations' mean haplotype diversity(h)and nucleotide diversity(π)were 0.5286±0.0489 and 0.0019±0.0013.HD and NM populations owing the highest genetic diversity due to their widely spread and highly complex geographic character in their living environments.DB,CHX and ZJC populations also had a high genetic diversity.DB population near the P.colehicus karpowi,and the gene introgression increasing it's genetic diversity;CHX population wan isolated by the forests in Huicheng basin and led to the most haplotypes,especially, Hap-4和Hap-5 were it's unique haplotypes;ZJC population had the highest genetic diversity,which resulted from introgression of the Phasianus colchicus torquatus.MX, ZHX,WW and NSH populations had small genetic differentiation within populations, and had high gene flow with other populations.Using Fu's Fs test(Fu,1997)to explain the evolutionary history of P.colchieus in northern China.Results showed that the evolutionary history weren't stable,and they had suffered a fast expansion,but things were variable among each population.ZHX,WW, HD,NSH and NM populations had spread out in their evolutionary history significantly; JN,NISH,SICH and SHCH populations just had one haplotype,which can't using the neutral test.Other populations were generally stable in history.We studied eight subspecies of P.colchicus in northern China.Except SICH and SHCH subspecies,other six subspecies shared haplotypes,and haplotypes exited in every subspecies.As each subspecies has its own realm,subspecies all had their own unique haplotypes except NISH subspecies,for fitting their living environments and the repeating various climate since Pleistocene.The unique haplotypes achieved seventeen, 81%of all haplotypes.HD subspecies owned the most haplotypes and unique haplotypes, NM subspecies was the second.Hap-21 belonged to SHCH subspecies,and had the furthest relationship with others.The phylogeography of eight subspecies was divided into two clades distinctly, SHCH subspecies evolved indepently.GSU,NSH,NISH had the nearest relationship in the phylogeography,and they had the smallest differentiation and the most gene flow. And the Fst indicted the differentiation between the three subspecies were smaller than the differentiations within the subspecies.All these suggested that NSH and NISH subspecies maybe a part of GSU subspecies,and denied the traditional classified way.The genetic structure of P.colchicus in northern China was greatly influenced by the uplift of Qinghai-Tibetan Plateau and glacier-inter-glacier effect.In the early Pleistocene, Qinghai-Tibetan Plateau has uplifted for a certain height,and made a geographic separation between SHCH population and others,limiting gene flow.SHCH population was evolved in 0.57-0.71 million years ago independently,and formed in SHCH subspecies.Other populations also divided into each subspecies during the population diffusion.There were some relations between genetic variance and morphological variance about P.colchicus in this study.