蛇鳄龟微卫星标记的开发及一个养殖群体的遗传多样性分析

利用磁珠富集法, 以生物素标记的(CA)15为探针, 构建了蛇鳄龟(Chelydra serpentina L.)微卫星富集文库。通过PCR法从富集文库中共筛选出70条微卫星序列, 一共设计了48对微卫星引物, 采用PCR扩增的方法从中筛选出36对引物, 对一个蛇鳄龟养殖群体进行遗传多样性分析。通过分析, 36个位点获得的等位基因数从29不等, 平均为4.361, 有效等位基因为1.4617.767, 平均为3.498。等位基因片段大小为56342 bp, 观测杂合度为0.0671.000, 平均为0.725; 期望杂合度为0.3160.850, 平均0.600; 多态信息含量为0.26550.8359, 平均为0.5573; 结果表明此蛇鳄龟养殖群体存在较高的遗传多样性水平。群体内固定系数-0.6880.856, 平均为-0.214, 说明蛇鳄龟群体中杂合子过剩。  

Isolation of microsatellite markers in the Common snapping turtle (Chelydra serpentina L.) and its application in genetic diversity analysis in a cultured population

To isolate and identify polymorphic microsatellite markers which would be used for evaluating the genetic diversity of Chelydra serpentina L. An enriched microsatellite library of C. serpentina was constructed by the magnetic-bead enrichment method used biotinylated (CA)15 probe. Screened the enriched microsatellite library by PCR amplification technique, seventy microsatellite sequences were obtained. To analyze genetic diversity of a cultured C. serpentina, forty eight pairs of primers were designed on the basis of the microsatellite sequences and 36 of that were screened by PCR amplification technique. In these microsatellite loci, the number of alleles per locus ranged from two to nine with an average of 4.361. The number of effective allele ranged from 1.461 to 7.767 with an average of 3.498. The size of allele fragment ranged between 56 and 342 bp. The observed heterozygosity varied from 0.067 to 1.000 with an average of 0.725. The expected heterozygosity varied from 0.316 to 0.850 with an average of 0.600. Polymorphism information content (PIC) ranged from 0.2655 to 0.8359 with an average of 0.5573. The average fixation index coefficient of population was -0.214, which suggested surplus heterozygotes in the population. These results indicated that the cultured C. serpentina populations have relatively high genetic diversity.