摘要
利用8个微卫星标记对7个乌龟养殖群体进行了遗传多样性和遗传结构的检测。结果显示,7个养殖群体都表现出较高的多态性,8个位点共检测出130个等位基因,范围在9～26,平均16.25;其多态信息含量(PIC)范围为0.57～0.92,平均值为0.71;观测杂合度(HO)和期望杂合度(HE)分别为0.30～0.87和0.60～0.93。分子变异方差分析(AMOVA)结果表明,遗传变异5.91%来自群体间,84.29%来自群体内部,两两群体间FST值在0.0143～0.1127,其中57.14%的两两群体间无分化,42.86%的两两群体间出现了中等程度的分化。哈迪-温伯格平衡检测表明,8个位点中有5个位点显著或极显著的偏离了哈迪-温伯格平衡,推测各群体中出现了近交繁殖的现象。7群体间遗传距离为0.1066～0.6468,UPGMA聚类分析表明,湖北荆州群体单独聚为一支,其余6个群体聚为另一支。另外,7个群体都存在特有等位基因,提示群体间等位基因扩散受到一定程度的限制,同时在育种上,可以作为亲本选育的一个重要参考指标。
Chinese pond turtle（Chinemys reevesii Gray,1831） is one of the main turtle species in China with commercial and medicinal importance,and it began to attract attention as a breeding species in 1990s and became one of the largest domestic breeding varieties.The population of farmed Chinese pond turtle increased in China,however,only little is known on the genetic status of this species.In this study,eight highly variable microsatellite loci were used to investigate genetic diversity and captive stocks structure of Chinese pond turtle in China.A total of 130 different alleles were detected in all examined loci.The number of alleles ranged from 9 to 26,with an average number of 16.25 per locus.The high number of alleles per locus within these stocks indicated the potential usefulness of these primers to characterize stock genetic structure of C.reevesii.The results demonstrated that seven stocks showed high polymorphic information content（PIC） values（ranged between 0.57 and 0.92） ,which is much higher than the standard value of 0.5,and the observed （HO ） and expected heterozygosity（HE） ranged from 0.30 to 0.87 and from 0.60 to 0.93,respectively.The analysis of molecular variance（AMOVA） indicated that almost majority of the variance in the C.reevesii was within stocks（84.29% ） ,and 5.91% was among stocks.All pairwise FST estimates between the seven stocks ranged from 0.014 3 to 0.112 7 and were also significantly different from zero（P 0.05） ,which showed that a low genetic divergence was between stocks.Hardy-Weinberg equilibrium analysis indicated that there were five loci in great significant Hardy-Weinberg disequilibrium,and each locus in each stock test showed that there were 19.64% （11/56） loci in significant genetic disequilibrium（P 0.05） ,14.29% （8/56） loci were at a very significant level（P 0.01） ,and the rest of the 66.07% （37/56） loci were in genetic equilibrium（P 0.05） .The most plausible explanation for heterozygote deficiency is inbreeding in this cultured stocks.Examination of linkage disequilibrium using Fisher’s exact test revealed that all eight loci were in linkage equilibrium（P 0.05 for each pair of loci across all samples） .The genetic distance and genetic similarity coefficient among stocks ranged from 0.106 6 to 0.646 8 and from 0.523 7 to 0.898 9,respectively.The dendrogram based on genetic distance showed two major clusters： the stock from Jingzhou,Hubei province（HBJZ） alone was in one cluster,which is sampled from the north of Yangtze River.The other cluster consists of individuals from sampling localities distributed in the south of Yangtze River.The isolation within C.reevesii may be attributed to Yangtze River,which acted as a barrier to block gene flow.Forty-four private alleles occurred within the seven C.reevesii stocks and only one in the HNHS stock,which compares with 14 private alleles in the SH stock.The discovery of unique alleles within the stocks supported the conclusion that these stocks had differentiated from each other and that gene flow had been restricted among stocks gradually.Thus,it may be possible to form a new superior broodstock with high genetic diversity by combining turtles from different stocks,and measures should be taken to prevent further loss of genetic diversity.
出处
《水产学报》
CAS
CSCD
北大核心
2010年第11期1636-1644,共9页
Journal of Fisheries of China
基金
国家自然科学基金项目(30970362)
关键词
乌龟
遗传多样性
微卫星
Chinese pond turtle （Chinemys reevesii）
genetic diversity
microsatellite
