基于线粒体COⅠ序列比较长江口中华绒螯蟹放流与野生群体的遗传多样性

Genetic diversity of Eriocheir sinensis in released and wild populations based on Mitochondrial Cytochrome Oxidase Subunit Ⅰ sequence from the Yangtze Estuary

为探讨长江口中华绒螯蟹(Eriocheir sinensis)放流亲蟹与野生群体的遗传多样性和遗传结构的差异,对77个放流和野生亲蟹个体进行了线粒体细胞色素氧化酶亚基Ⅰ(COⅠ)基因序列的比较分析,结果表明:所检测的样本共计77个COⅠ基因序列(630 bp)中,变异位点(V)41个,简约信息位点(P)37个,A+T(61.7%)的含量明显高于C+G(38.3%),表现出较为明显的碱基组成偏倚性;两个群体共检测出15种单倍型,其中单倍型Hap-1出现频率最大,为两个群体所共享,放流和野生群体各具有5种独有单倍型;两个群体的单倍型多样性指数(H)为0.825,核苷酸多样性指数(π)为0.004 66,平均核苷酸变异数(K)为2.910,其中野生群体的单倍型多样性指数(0.833)和核苷酸多样性指数(0.007 70)均高于放流群体(0.810和0.002 11)。AMOVA分子方差分析表明,长江口中华绒螯蟹放流与野生群体总的遗传变异主要来自群体内,其中96.53%遗传变异来自各群体内部,3.47%遗传变异来自群体间。群体内遗传分化指数(FST)野生群体(0.034 75)高于放流群体(0.034 57),两个群体间遗传分化指数(FST)为0.034 66(P>0.05),两个群体遗传分化不显著。两个群体间的基因流(Nm)为13.93(Nm>1),表明放流群体和野生群体的基因交流较为频繁。

Chinese Mitten Crab,Eriocheir sinensis,is an important economic crab in China. The crab population has decreased greatly in recent years due to over-exploitation and large-scale water conservation construction in the Yangtze River. To restore the natural resources of Chinese mitten crab in the Yangtze River,measures have been taken by provinces and cities along the Yangtze River,such as taking artificial stocking measures. In this study,Mitochondrial Cytochrome Oxidase Subunit Ⅰ（ COⅠ） fragments of released and wild Eriocheir sinensis from the Yangtze Estuary were amplified via PCR,then PCR products were purified and sequenced. The population genetic diversity and structure by sequencing the mitochondrial COⅠ gene of77 individuals were analyzed. Results showed that there were 41 variable sites in total 630 sites and 15 haplotypes were found among 77 individuals of released and wild Eriocheir sinensis. Among the total 15 haplotypes,Hap- 1 appeared most frequently in released and wild Eriocheir sinensis and was shared with two populations. Hap- 3,Hap- 5,Hap- 6,Hap- 13 and Hap- 14 were unique for the released population while Hap- 10,Hap- 11,Hap- 12,and Hap- 15 were unique for the wild. The total genetic diversity indexs were high. Haplotype diversity index（ H） was 0. 825,nucleotide diversity index（ π） was 0. 004 66,and the average number of nucleotide variation index was 2. 910. Analyzing separately the genetic diversity of two populations,we found that haplotype diversity and nucleotide diversity index of the wild population were higher than that of the released population. The haplotype diversity index of two populations was 0. 833 and 0. 810. The nucleotide diversity index of two populations was 0. 007 70 and 0. 002 11. Analysis of molecular variance（ AMOVA） showed that the genetic differentiation index（ FST） of two populations was 0. 034 66（ P〉0. 05）,indicating obvious genetic differences among the released and wild individuals,and the genetic variation mainly existed within populations. Index of genetic differentiation（ FST） and gene flow（ Nm） between released population and wild population were 0. 034 66 and 13. 93,indicating that there were more frequent gene flows between two populations（ Nm= 75. 05〉1）.