| Hucho taimen which belongs to Samoniformes，Salmonidea, Hucho genus is alarge cold water fish,and it is a endangered species.It is also a good kind of freshwateraquaculture.In this research,some Microsatellite markers and the control region ofmitochondrial DNA are used to Analysis the Genetic Diversity on several WildStocks of taimen(Hucho taimen) in Heilongjiang River Valley， including thefollowings:9wild populations of taimen are investigated using20microsatellite markers. Theresults showed that the observed heterozygosity is between0.0994-0.8882, the expectedheterozygosity is between0.2005-0.8759, and the PIC index is between0.3432-0.5261while population from Huma River has low genetic diversity. FST of matching group isbetween0.0246-0.2333（P<0.0001）and Nm is between0.8216-9.9292, which indicatedthat the genetic differentiation was remarkable among populations, and the gene flowswas low; the migration rate between populations were inconsistent, the immigratory rateand migratory rate in each population were asymmetrical, and the trend was the largepopulation migrated to the small population. The half/full-sib family tests detected aproportion of half/full-sib family groups between27.78%-90.91%, showing a highinbred pressure and a risk of bottlenecks experienced by most groups. The AMOVAresults showed that the global FST was0.1081; the clustering result and the analysisof the genetic composition showed that all individuals from Huma River and WusuliRiver clustered as one clade, and all individuals from the upper reaches of theHeilongjiang River clustered as another clade.Primers were designed to using PCR technology for10wild taimen groups of total42individuals’ mtDNA D-loop region of sequence amplification and sequencing to get the sequence right.Found the50sequences of length variation, select a total of555bpsequence alignment to analysis. Sequences using the MEGA (version4.0) and DnaSP(version4.0) software to calculate, results showed that:42taimen mitochondrialsequences in D-LOOP, A, T, G and C nucleotide content of an average of30.2%,31.3%,15.8%and22.7%.This is similar to other fish that have been reported inD-LOOP base.42individuals showed28haplotypes, including28polymorphic sites,haplotype diversity index is between0.733-1.000and the nucleotide diversity index (PI)is between0.00156-0.01444. The genetic diversity level of these groups is verydifference. The group of Gen River (GH) with high genetic diversity and the Hu tou(HT), Zhua ji (ZJ), Haiqing (HQ), Huma (HM)section of the river are of low geneticdiversity. Cluster analysis also shows that the42individuals, even if betweengeographically closer to groups the gene flow is less than normal. There are obviousgenetic differentiation between groups.All the results indicated that the decrease of taimen resource effected the geneexchange between populations, we should put an end to the destructive fishing fortaimen while enhancing gene exchange between populations in order to achieve fullprotection of taimen germplasm resources. |
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