中国野桑蚕mtDNA中A+T丰富区片段的克隆及序列分析

对中国野桑蚕mtDNAA +T丰富区片段进行了克隆和序列分析。在所测定的 72 0bp左右的片段中 ,A +T含量为 92 0 8% ,与不同家蚕品种的mtDNA相近 ,中国野桑蚕与家蚕之间的核苷酸序列呈高度同源性 (98%以上 ) ;但与日本野桑蚕相比 ,中国野桑蚕mtDNA的A +T丰富区片段 ,缺少 2个 12 6bp的重复单位 ,A +T含量低 0 9% ,核苷酸序列同源性也较低 (72 % )。该片段与中系家蚕mtDNA比较 ,有 15个变异位点。对mtDNAA +T丰富区的中国野桑蚕和日本野桑蚕及中系、日系和韩国的 4个家蚕品种进行聚类分析表明 ,日本野桑蚕有可能由中国野桑蚕分化而来。

Cloning and Sequence Analysis of the A + T Rich Region Segment of mtDNA From Chinese Bombyx mandarina M.

The A+T-rich fragment of mitochondrial DNA (mtDNA) from the Chinese Bombyx mandarina M.were cloned and sequenced.It indicated that the content of A+T in sequenced 720 bp fragment is similar to those of mtDNA from different species of B.mori,is about 92 8%,there were high homology (more than 98%) among different species of B.mori and Chinese B.mandarina M. in nucleotide acid level,but while compared with Japanese B.mandarina M.,it was found that two repeated units of 126 bp sequence were lacked in A+T-rich fragment of mtDNA from Chinese B.mandarina M.,the content of A+T is 0 9% lower than that of Japanese B.mandarina M.,and the nucleotide acid homology is lower(72%).And there are 15 variation sites in this fragment compared with Chinese B.mori. Furthermore,the phylogenetic analysis of Chinese and Japanese B.mandarina M.,and the B.mori of China,Japan and Korea indicates that Chinese B.mandarina M. and Japanese B.mandarina M. located on same branch,and it was possible that Japanese B.mandarina M. is evolved from Chinese B.mandarina M..