不同地理种群银杏大蚕蛾COI基因序列变异与遗传分化

银杏大蚕蛾Caligula japonica是亚洲东部的特有种, 既是一种重要的林业害虫, 也是一种珍贵的野生蚕类资源。为了揭示银杏大蚕蛾地理种群间的内在联系, 测定了我国分布的12个地理种群的线粒体细胞色素氧化酶C亚基I（COI）基因部分序列（GenBank登录号: FJ358506-FJ358517）, 对地理种群间的序列变异和遗传分化进行了分析。结果表明: 银杏大蚕蛾地理种群间的COI序列同源性高达99%~100%, 显示出比较小的遗传差异。序列对准后从供试COI序列中仅鉴定出9个变异位点和6个单元型, 其中3种是共享单元型。系统发育分析结果表明种群间已经按地理位置形成了一定的地理格局, AMOVA分析显示北方组和南方组之间已经具有明显的遗传分化（FST=0.478, P<0.001）。综合分析, 我们认为北方组和南方组之间的遗传分化可能与差异巨大的生态条件有关。研究结果为银杏大蚕蛾的种群遗传学和生态学研究提供了一个基本的分子生物学线索。

Sequence variability of COI gene and genetic differentiation among the geographic populations of Caligula japonica (Lepidoptera:Saturniidae) in China

Caligula japonica, an endemic species in eastern Asia, is not only an important forestry pest to be controlled, but also a precious wild silkmoth resource to be domesticated for silk production. In order to clarify the genetic relationship of the geographic populations of C. japonica, we determined the 574 bp segment of the mitochondrial cytochrome oxidase subunit I (COI) gene sequences from 12 geographic populations in China (GenBank accession no. FJ358506-FJ358517), and then analyzed the sequence variability of the COI gene and genetic differentiation among them. The identity of COI pairwise sequences was 99%-100% among the geographic populations of C. japonica, which indicated a low genetic diversity. In total, six haplotypes were identified within the sequences, with nine sites showing polymorphism and three haplotypes shared. Molecular phylogeny analysis showed that populations sampled were well divided into “Northern” and “Southern” groups. AMOVA analysis showed that there were apparent genetic differentiation between the “Northern” group and the “Southern” group (FST=0.478, P<0.001). It is inferred that the genetic differentiation between the “Northern” group and the “Southern” group should be related to ecology adaptation of C. japonica. The results of this study provide a basic molecular biology clue to the studies on population genetics and ecology of C. japonica.