广西地区中华圆田螺不同地理种群遗传多样性分析

Genetic Diversity Analysis of Different Geographical Populations of Cipangopaludina cathayensis in Guangxi Region

关键词:  中华圆田螺  广西地区  微卫星  遗传多样性  遗传分化

Key words:  Cipangopaludina cathayensis  Guangxi region  microsatellite  genetic diversity  genetic differentiation

摘要:

为探究珠江流域广西境内中华圆田螺(Cipangopaludina cathayensis)种群的遗传多样性特征，本研究采用12对微卫星引物对广西地区中华圆田螺10个地理种群的遗传多样性和遗传分化进行分析。结果显示：12个微卫星位点共检测到140个等位基因，多态信息含量(PIC)为0.373-0.923，其中有9个为高度多态性位点，有3个为中度多态性位点。10个地理种群的香农信息指数(I)为0.415-1.226，观测杂合度(Ho)为0.231-0.540，期望杂合度(He)为0.239-0.608，说明这些种群具有较高的遗传多样性。分子方差分析(AMOVA)结果显示，种群内的遗传变异占75%，种群间的遗传变异占25%，遗传分化指数(Fst)为0.248，种群间的遗传分化程度较高。基因流(Nm)为0.391-21.807，除河池都安(HCDA)种群和百色那坡(BSNP)种群外，其余8个种群间的基因交流频繁(Nm>1.000)。种群结构分析发现，BSNP种群与玉林陆川(YLLC)种群的遗传距离较远(D=0.047)，遗传分化程度较高(Fst=0.277)。聚类分析和主坐标分析(PCoA)结果显示，HCDA种群和BSNP种群单独为一支，表明这两个种群与其他种群亲缘关系较远。Mantel分析发现，地理距离不是影响各种群间遗传距离大小的主要原因。综上，广西地区中华圆田螺种质资源良好，其中HCDA种群和BSNP种群仍保持着较好的野生资源，具有潜在的开发利用价值。

Abstract:

In order to explore the genetic diversity characteristics of Cipangopaludina cathayensis population in Guangxi, the Pearl River Basin,China，12 pairs of microsatellite primers were used to analyze the genetic diversity and genetic differentiation of 10 geographical populations of C.cathayensis in Guangxi. The results showed that a total of 140 alleles were detected at 12 pairs of microsatellite loci, and the Polymorphic Information Content (PIC) was in the range of 0.373-0.923, of which 9 were highly polymorphic loci and 3 were moderately polymorphic loci. The Shannon information index (I) of the 10 geographical populations was 0.415-1.226, the observed heterozygosity (Ho) was 0.231-0.540 and the expected heterozygosity (He) of 0.239-0.608, which indicated that these populations had high genetic diversity. The results of Analysis of Molecular Variance (AMOVA) showed that the genetic variation within populations accounted for 75%, and the genetic variation among populations accounted for 25%.The genetic differentiation index (Fst) was 0.248, and the genetic differentiation among populations was higher. The gene flow (Nm) was 0.391-21.807,and the gene exchange was frequent among the remaining 8 populations (Nm>1.000) except for the Hechi Du'an (HCDA) and Baise Napo (BSNP) population. The analysis of population structure showed that the genetic distance between BSNP population and Yulin Luchuan (YLLC) population was relatively far (D=0.047), and the degree of genetic differentiation was high (Fst=0.277). The results of cluster analysis and Principal Coordinate Analysis (PCoA) showed that the HCDA and BSNP population were in a separate branch, indicating that this two populations was more distantly related to other populations. Mantel analysis found that geographical distance was not the main factor affecting the genetic distance among populations. In summary, the germplasm resources of C.cathayensis in Guangxi are good, and the HCDA population and BSNP populations still maintain good wild resources, which have potential development and utilization value.