大额牛HSL基因外显子Ⅰ部分片段的序列测定及分析

Sequence and analysis of part ExonⅠof Gayal(Bos frontalis) HSL gene

对大额牛HSL基因外显子Ⅰ部分序列进行PCR扩增、测序及氨基酸预测,并同其它牛种的资料进行了比对分析,构建了分子系统进化树。结果表明:大额牛其核苷酸序列与牦牛、普通牛、瘤牛、水牛间的同源性分别为99.6%、99.4%、99.2%、97.0%。相应的氨基酸序列大额牛与水牛的同源性为97.6%;与普通牛、瘤牛、牦牛的同源性均为99.4%,仅在第33位有1个氨基酸变异,即大额牛为异亮氨酸,而其它3个牛种均为缬氨酸,这是由该基因片段的第97位碱基发生转换(A←→G)造成的。从分子系统进化树看,瘤牛和普通牛先聚为一类,再依次与牦牛、大额牛、水牛相聚,这与传统的牛种分类结果一致。

Part of HSL gene in the gayal （Bos frontalis） was amplyfied by PCR, sequenced and conceptually translated to amino-acids. Then these arrays were compared with those of cattle （Bos taurus）, zebu （Bos indicus）, yaks （Bos grunniens） and buffalo （Bubalus bubalis）, and the molecular phylogenetic tree was constructed. The results showed that： the homologies between the gayal and other 4 bovidaes were all relatively high. The homology between the gayal and the yak, cattle, zebu, buffalo was 99. 6%, 99.4%, 99. 2%, 97.0% respectively. Comparision on the amino-acid arrays showed that ： the homology between the gayal and the buffalo was 97.6%, which was the lowest, and it was all 99.4% between the gayal and others. Besides, only a mutation was observed at the 33rd amino-acid between the gayal and the cattle, zebu and yak, there was an I at the 33rd position in the gayal comparing with a V in others, which was due to the base transition （A ←→G） at the 97th site of the gene fragment. But it was valuable to do more advanced research on that whether the mutation was relative to the meat quality of the gayal. Molecular phylogenetic tree indicated thatzebu were clustered together with cattle firstly, then with the yak, followed by the gayal, and the buffalo was clustered together finally, which was accordance with the traditional classification results.