基于COI基因的浙江省内黄缘闭壳龟遗传多样性研究

Genetic Diversity Analysis of Cuora flavomarginata Based on COI Genes in Zhejiang Province

为了解浙江省内不同黄缘闭壳龟(Cuora flavomarginata)群体的种质资源现状,基于线粒体DNA COI序列对来自浙江省内野外和养殖场的8个黄缘闭壳龟群体的遗传多样性和遗传结构进行比较分析。结果表明:黄缘闭壳龟线粒体COI基因序列长度为1040 bp,A=27.4%、T=30.5%、C=24.6%、G=17.5%,有较强的AT偏好性;共定义9个单倍型,单倍型多样性(Hd)为(0.79900±0.21000),核苷酸多样性(Pi)为(0.00209±0.00147),呈“高Hd低Pi”遗传分布;不同黄缘闭壳龟群体间的遗传距离为0~0.003,群体内部的遗传距离为0~0.004,其中磐安后阁村(YS)群体内部的遗传距离最大,为0.004;单倍型系统发育树并未呈现明显的谱系结构;群体间遗传分化指数(FST)为-0.34752~0.82222,8个群体的遗传分化不显著(p>0.05);中性检验(Tajima’s D=-0.36627,Fu’s FS=-0.605)与核苷酸错配分布均表明,浙江省内黄缘闭壳龟群体并未经历种群扩张事件,同时,由Mantel检验可知,遗传距离与地理距离没有显著的相关性(R=0.2938,p>0.05);AMOVA分子方差结果显示,群体内的遗传变异高于群体间(85.06%>14.94%)。研究表明,浙江省内黄缘闭壳龟群体之间为高单倍型多样性和低核苷酸多样性的遗传特征,并且存在一定水平的遗传分化,群体内存在明显的基因交流,根据COI基因分析显示,在磐安县获得的野生黄缘闭壳龟个体确定为黄缘闭壳龟浙江种,同时也发现存在浙江种与安徽种的杂交种,建议将分化程度不同的黄缘闭壳龟群体划分为不同单元保护。研究结果为浙江省内黄缘闭壳龟种质资源开发利用和合理制定保护措施提供了基础依据。

In order to understand the present situation of germplasm resources of different Cuora flavomarginata in Zhejiang Province,the genetic diversity and genetic structure of eight C.flavomarginata populations from wild and breeding farms in Zhejiang Province were compared based on mitochondrial DNA COI sequence.The results showed that the sequence length of COI gene of C.flavomarginata was 1,040 bp,and the average base content was A=27.4%、T=30.5%、C=24.6%、G=17.5%,with strong AT preference.Nine haplotypes were identified in the eight populations,and the haplotype diversity(Hd)was(0.79900±0.21000),and the nucleotide diversity(Pi)was(0.00209±0.00147),showing“high Hd and low Pi”genetic distribution.The genetic distance between different populations ranged from 0 to 0.003.The genetic distance within populations was between 0 and 0.004,among which the genetic distance within Pan’an Houge Village(YS)population was the largest,which was 0.004.The haplotype phylogenetic tree did not show obvious pedigree structure.The genetic differentiation index(FST)interval was from-0.34752 to 0.82222,and the genetic differentiation was not significant(p>0.05)in eight populations.Tajima’s D and Fu’s FS test values were either positive(Tajima’s D=-0.36627,Fu’s FS=-0.605),but statistically insignificant.The distribution of nucleotide mismatches indicated that the population of the C.flavomarginata in Zhejiang Province did not experience a population expansion event.Mantel test showed that there was no significant correlation between genetic distance and geographical distance(R=0.2938,p>0.05).AMOVA analysis found that the genetic variation within populations was higher than that between populations(85.06%>14.94%).The results showed that the populations of C.flavomarginata in Zhejiang Province are characterized by high haplotype diversity and low nucleic acid genetic diversity,and there was a certain level of genetic differentiation,and there was obvious gene exchange among the populations.The wild C.flavomarginata obtained in Pan’an County was identified as Zhejiang species according to COI gene analysis.Moreover,it was also found that there were hybrids between Zhejiang species and Anhui species.It is suggested that the C.flavomarginata populations with different degrees of differentiation should be divided into different units for protection.This study uses genetic diversity analysis to provide a basis for the development and utilization of C.flavomarginata germplasm resources in Zhejiang Province and the formulation of reasonable protection measures.