基于线粒体COI基因序列的5种鲤养殖品种遗传多样性研究

Study of DNA barcoding and genetic variation based on the mitochondrial COI gene sequences in five carp varieties

本研究通过对5个鲤养殖品种即高寒鲤（Cyprinus carpio Frigid carp）、松浦鲤（Cyprinus carpio Songpu carp）、蓝鳞鲤（Cyprinus carpio blue var）、松浦镜鲤（Cyprinus carpio Songpu mirror carp）和红镜鲤（Cyprinus carpio Red mirror carp）的线粒体COI基因部分序列的测定, 比较并分析了其遗传多样性和系统进化关系。在5个鲤品种共100个样本的线粒体COI序列中检测到8种单倍型, 其中5个单倍型（H1、H2、H4、H5、H6）涵盖样本较多, 占总样本数的94.06%。蓝鳞鲤的单倍型数最少, 仅有1个, 红镜鲤单倍型数为2个, 其余3个品种的单倍型数均为5个。5个品种单倍型多样性（Hd）在0.160±0.070-0.811±0.055, 其中, 遗传多样性最高的为高寒鲤。AMOVA结果表明, 品种间变异（50.28%）略高于品种内变异（49.72%）, 各品种间的FST值在0.711 4-0.831 2, 其中蓝鳞鲤与其他群体之间差异最大。用MEGA4.0软件构建的基于遗传距离的进化树表明, 5个养殖品种中, 高寒鲤和红镜鲤的遗传距离最近（D=0.31）, 聚为一支; 松浦镜鲤和松浦鲤的遗传距离较近（D=0.33）, 聚为一支; 蓝鳞鲤与其他品种存在较大遗传差异, 单独形成一个分支。除蓝鳞鲤外, 其余4个养殖品种间均存在共享的单倍型（H2、H4、H5、H6）, 可能是由于其在选育过程中亲本的遗传背景存在交叉, 同时也证明DNA条码在分析种内品种间遗传关系时具有可行性但具有一定的局限性。

The mitochondrial COI gene of five cyprinoid aquaculture varieties were sequenced and their genetic diversity and cluster analysis were compared. Eight haplotypes were detected from 100 individuals, of which 94.06 % belonged to five haplotypes （H1, H2, H4, H5, H6）. Cyprinus carpio blue var has only one haplotype, C. c. Red mirror carp has two haplotypes, and the other varieties including Cyprinus carpio Frigid carp, C. c. Songpu carp and C. c. Songpu mirror carp had five. Haplotype diversity （Hd） was 0.160±0.070 ~ 0.811±0.055, the highest Hd frequency was observed in Frigid carp. The AMOVA and cluster analysis revealed that genetic distance between varieties （50.28%） was a little higher than that within varieties （49.72%）, and the FST ranged from 0.711 4？0.831 2. Compared with the others varieties, Cyprinus carpio blue var exhibited the biggest differences. According to the evolutionary tree based on genetic distance, five varieties could be divided into three groups, the first group included Frigid carp and Red mirror carp, the second included Songpu mirror carp and Songpu carp, and the last included Cyprinus carpio blue var. With the exception of Cyprinus carpio blue var, all varieties shared the same haplotypes （H2, H4, H5, H6）, which may be due to cross breeding. This study also indicated that DNA barcoding is a practical tool for analyzing the hereditary of different varieties. However, some limitations still exist.