Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and popula...Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems, two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank. Basic statistics showed that the average observed heterozygosity （Ho） amongst populations ranged from 0.5789 to 0.6824. However, a remarkable presence of inbreeding and heterozygote deficiencies were observed. To analyze population structure, pairwise FST coefficients explained only -10.3% variability from the subdivision of mitten crab populations, the remaining variability stems from the subdivision within subpopulations. Although the four populations had slight differentiation, different allelic frequencies resulted in distinct population structures. Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab, with an approximate membership of 95%. Whereas, another farming population was clustered singly to the phylogenetic branch of the Liaohe crab, with a membership of 97.1%. The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems. Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.展开更多
A library rich in CA/GT microsatellites was constructed from the Paralichthys olivaceus genome by combining biotin capture method and radioactive labeling hybridization.Five hundred and twenty six positive clones were...A library rich in CA/GT microsatellites was constructed from the Paralichthys olivaceus genome by combining biotin capture method and radioactive labeling hybridization.Five hundred and twenty six positive clones were obtained through twice screens.Sequencing confirmed 133 microsatellite loci(number of repeats t〉5)in 119 positive clones.Of these microsatellites,two(1.5%)had compound repeat motifs,63(47.37%)had perfect motifs and 68(51.13%)had imperfect motifs.Primer pairs were designed in the flanking regions of 22 microsatelites and subjected to PCR amplification.In 8 artificial gynogenesis families,four pairs failed to amplification,one pair was monomorphic,and the rest were polymorphic with an average of 5.2 alleles per locus.Heterozygosities ranged between 0.375 and 0.846,PIC ranged between 0.305 and 0.823.The results suggested that most of the microsatellites we isolated were qualified to be applied to the population genetic studies of P.olivaceus.展开更多
The germplasm of breeding large yellow croaker （Pseudosciaena crocea Richardson） was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Dai...The germplasm of breeding large yellow croaker （Pseudosciaena crocea Richardson） was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min - Yue stocks and two hybrid groups, as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity. The value of pair- wise differentiation coefficient（ FST ） was only 13. 1% between Daiqu and Min -Yue stocks, demonstrating the low level of differentiation and a close relationship. However, STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different populations of the same species with distinct genetic structures. Examinations of individual admixture showed that Min - Yue stock had been contaminated by alien individuals. Moreover, the genetic structures of the two hybrid groups resembled those of their parents, especially affected more by their female parents. Finally, the values of average observed heterozygosity between parents and their ascendants were compared and tested, as a result of no detectable differences （P 〉 0. 05）.展开更多
文摘Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems, two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank. Basic statistics showed that the average observed heterozygosity （Ho） amongst populations ranged from 0.5789 to 0.6824. However, a remarkable presence of inbreeding and heterozygote deficiencies were observed. To analyze population structure, pairwise FST coefficients explained only -10.3% variability from the subdivision of mitten crab populations, the remaining variability stems from the subdivision within subpopulations. Although the four populations had slight differentiation, different allelic frequencies resulted in distinct population structures. Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab, with an approximate membership of 95%. Whereas, another farming population was clustered singly to the phylogenetic branch of the Liaohe crab, with a membership of 97.1%. The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems. Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.
文摘A library rich in CA/GT microsatellites was constructed from the Paralichthys olivaceus genome by combining biotin capture method and radioactive labeling hybridization.Five hundred and twenty six positive clones were obtained through twice screens.Sequencing confirmed 133 microsatellite loci(number of repeats t〉5)in 119 positive clones.Of these microsatellites,two(1.5%)had compound repeat motifs,63(47.37%)had perfect motifs and 68(51.13%)had imperfect motifs.Primer pairs were designed in the flanking regions of 22 microsatelites and subjected to PCR amplification.In 8 artificial gynogenesis families,four pairs failed to amplification,one pair was monomorphic,and the rest were polymorphic with an average of 5.2 alleles per locus.Heterozygosities ranged between 0.375 and 0.846,PIC ranged between 0.305 and 0.823.The results suggested that most of the microsatellites we isolated were qualified to be applied to the population genetic studies of P.olivaceus.
基金The National High Technology Research and Development Program of China under contract No.2006AA10A405
文摘The germplasm of breeding large yellow croaker （Pseudosciaena crocea Richardson） was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min - Yue stocks and two hybrid groups, as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity. The value of pair- wise differentiation coefficient（ FST ） was only 13. 1% between Daiqu and Min -Yue stocks, demonstrating the low level of differentiation and a close relationship. However, STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different populations of the same species with distinct genetic structures. Examinations of individual admixture showed that Min - Yue stock had been contaminated by alien individuals. Moreover, the genetic structures of the two hybrid groups resembled those of their parents, especially affected more by their female parents. Finally, the values of average observed heterozygosity between parents and their ascendants were compared and tested, as a result of no detectable differences （P 〉 0. 05）.
