洪泽湖河蚬(Corbicula fluminea) 2种表型群体的遗传变异分析

Genetic Variation in Two Phenotypical Populations of Corbicula fluminea in Hongze Lake

中文关键词: 河蚬  细胞色素氧化酶I  遗传多样性  分子方差分析  洪泽湖

英文关键词: Corbicula fluminea  COI  Genetic diversity  AMOVA analysis  Hongze Lake

中文摘要:

      采用形态学分析(壳长、壳宽和壳高)和分子标记技术(细胞色素氧化酶I基因, COI)对洪泽湖河蚬(Corbicula fluminea)黄色和黑色2个群体的形态和遗传多样性特征进行研究。形态参数统计分析结果显示，2个群体的形态特征之间有显著性差异。经PCR扩增和序列测定，获得614 bp COI基因序列，2个群体的COI基因序列的碱基组成高度一致，均表现出A+T的含量(64.8%)明显高于G+C的含量(35.2%)。28个黑色个体发现7种单倍型，单倍型多样性和核苷酸多样性分别为0.794和0.04274；30个黄色个体发现5种单倍型，单倍型多样性和核苷酸多样性分别为0.607和0.02825。单倍型之间的遗传距离在0.002-0.091之间，其NJ和MP系统发生树表明，COI基因单倍型聚为 2个明显分支。分子方差分析(AMOVA)结果显示，Fst = 0.21736 (P<0.01), 21.74%的变异来自群体间，78.26%的变异来自群体内，2个群体之间有显著的遗传分化。研究表明，应将洪泽湖河蚬黑色和黄色群体分别作为独立单元进行管理和保护。

英文摘要:

      In order to better manage and protect the genetic resources of Corbicula fluminea in Hongze Lake, molecular marker (mitochondrial cytochrome oxidase subunit I gene sequence, COI) and morphometric parameters (wet weight, shell length, width and height) were used to investigate the differences in genetic diversity and morphological characteristics of two populations with different morphology in color: black and yellow. Morphological analysis showed that the morphological parameters were significantly different between two populations. Using PCR amplification and sequencing, 614 bp of COI sequences were obtained. The base composition of COI sequences were very similar between black and yellow populations, in which the A+T content was higher than the G+C content. Seven haplotypes were found among 28 black individuals; the haplotype and nucleotide diversity were 0.794 and 0.04274, respectively. In parallel, 5 haplotypes were found among 30 yellow individuals, with the haplotype and nucleotide diversity being 0.607 and 0.02825, respectively. The genetic distance varied between 0.002 and 0.091 among all the COI haplotypes. Molecular phylogenetic trees were constructed using neighbor- joining and maximum parsimony, suggested that the COI gene haplotypes clustered into two clades. Analysis of molecular variance (AMOVA) based on COI sequences suggested that 78.26% variation occurred within the population, and a lower percentage of 21.74% variation occurred between two populations, and there was significant genetic differentiation in both populations (Fst=0.21736, P<0.01). The present results suggested that black and yellow C.fluminea populations in Hongze Lake should be protected and managed as two independent units in genetic resource.