基于线粒体COⅠ基因的9个青鱼群体遗传变异分析

GENETIC DIVERSITY OF MITOCHONDRIAL COⅠ GENE IN POPULATIONS OF BLACK CARP FROM THE YANGTZE RIVER AND PEARL RIVER

为掌握中国青鱼(Mylopharyngodon piceus)种质资源分布特征,揭示青鱼种质资源的遗传变异情况,研究通过对9个青鱼群体271个样本线粒体COⅠ区设计引物并进行PCR扩增,运用软件分析了群体内部遗传多样性和各群体之间的进化关系。分析结果表明:长度为1003 bp的9个群体COⅠ基因区域序列GC含量低于AT含量,共检测到6个突变位点,7种单倍型,其中Hap4单倍型在9个群体中都有分布。AMOVA分子方差分析显示271个青鱼样本的变异90.33%来自群体内部,9.67%来自群体间。青鱼总体核苷酸多样性(π)偏低,在0.00109—0.00244。单倍型多样(H_(d))性较高,在0.403—0.847。遗传分化系数(F_(st))在–0.0033—0.23445,保持在低度至高度分化,主要集中在低度和中度分化。分析得到广东佛山群体可能经历过瓶颈效应,其余8个群体可能经历过快速的种群扩张事件。研究结果揭示了中国目前青鱼种质资源的遗传背景,可以为中国青鱼种质资源的保护和创新利用提供重要的参考依据。

Mylopharyngodon piceus is one of the four major fish and plays a very important role in ensuring the supply of aquatic products in China. In recent years, due to the destruction of wild resources and the intervention of artificial factors, the wild resources of M. piceus have been destroyed, and there is also a lack of corresponding data on the selection and breeding of improved M. piceus. In order to master the distribution characteristics and reveal the genetic variation of M. piceus germplasm resources, this study designed primers for 271 samples of mitochondrial COⅠ region of 9M. piceus populations and conducted PCR amplification. The genetic diversity and the evolutionary relationships among populations were analyzed by softwares. The results showed that GC content was lower than AT content in the COⅠ gene region of 9 populations with the length of 1003 bp. A total of 6 mutation sites and 7 haplotypes were detected, and Hap4 haplotypes were distributed in 9 populations. AMOVA showed that 90.33% of the variation of 271 M.piceus samples came from within and 9.67% from between populations. The total nucleotide diversity(π) of M. piceus was low, ranging from 0.00109 to 0.00244. Haplotype diversity(H_(d)) was high, ranging from 0.403 to 0.847. The coefficient of genetic differentiation(F_(st)) ranged from –0.0033 to 0.23445, and remained low to high, mainly concentrated in low and moderate differentiation. The results showed that the Foshan population may have experienced bottleneck effect, and the other 8 populations may have experienced rapid population expansion. The results of this study reveal the genetic background of Chinese M. piceus germplasm resources, which can provide important reference for the conservation and innovative utilization.