家蚕、野桑蚕线粒体Cyt b基因片段序列分析及分子进化研究

以家蚕中系一化地理品种延吉、印度多化品种迈索尔、欧系一化品种法 4 0 8油和中国镇江地区野桑蚕为材料 ,采用PCR技术扩增了其线粒体 (mitochondrialDNA ,mtDNA)细胞色素b(cytochromeb ,Cytb)基因 ,测定其 5′端5 91bp的核苷酸序列 ,并从GenBank中调取中系家蚕品种C10 8、夏芳 ,日系家蚕品种青熟 ,韩国家蚕品种Backokjam和日本野桑蚕的相应序列 ,进行同源性比较 ,发现日系家蚕品种青熟 ,印度家蚕品种迈索尔 ,欧系家蚕品种法 4 0 8油 ,韩国家蚕品种Backokjam和中系家蚕品种C10 8、延吉序列间的同源性最高 ,相互间均为 10 0 % ;日本野桑蚕与各家蚕品种序列间的同源性约 94 %～ 95 % ;中国野桑蚕与各家蚕品种序列间同源性约 98%～ 99%。分子进化树分析显示日本野桑蚕和各家蚕品种相应序列的分歧时间远远早于中国野桑蚕与各家蚕品种序列的分歧时间 ,这是在分子水平上证实家蚕起源于中国野桑蚕的证据之一。

Analysis of Segment Sequences and Molecular Evolution Between Bombyx mori and Bombyx mandarina Using Mitochondrial Cyt b Gene

Three Bombyx mori strains, including Chinese monovoltine geographical strain Yanji, Indian multivoltine strain Mysore and European monovoltine strain France 408-translucent, and Bombyx mandarina in Zhenjiang region in China were chosen as materials. Using PCR method, their mitochondrial cytochrome b (Cyt b) gene were amplified, then Cyt b gene 5′ end segment sequences ( 591 bp ) were sequenced, respectively. Also, corresponding sequences of B. mori strains Chinese C108, Xiafang, Japanese Aojuku and Korean Backokjam, and Japanese B. mandarina were obtained through GenBank search. Homology comparison of the corresponding sequences, the results showed that the homogeneous relationships among the sequences of all B. mori strains except Xiafang are 100%, while the homogeneous relationships between the sequences of B. mori and Zhenjiang B. mandarina (98%～99%) are closer than that between B. mori and Japanese B. mandarina (94%～95%). The analysis of phylogenetic tree revealed that the divergent time between the sequences of Japanese B. mandarina and B. mori strains selected is very earlier than that between Chinese B.mandarina and B. mori strains selected, which is one of the evidences of B. mori originated from Chinese B. mandarina molecular level.