CAJ | 학술논문

在对牛科中4种动物即牦牛、瘤牛、普通牛和水牛HSL基因外显子Ⅰ部分核苷酸序列进行测定的基础上,与GenBank中其他物种相应基因核苷酸序列、氨基酸序列进行了比对分析,并构建了牦牛与其他物种间分子系统进化树.结果表明:牦牛与普通牛、瘤牛、水牛、猪、人、小鼠、大鼠7个物种HSL基因外显子Ⅰ部分核苷酸序列间保守性较高,同源性大小依次为99.8%、99.6%、97.4%、90.6%、88.4%、83.5%、82.3%.相应氨基酸序列间保守性更高,同源性分别为100%、100%、98.2%、94.0%、92.2%、89.8%、89.8%.牦牛与各物种该基因部分核苷酸序列间碱基变异类型主要表现为碱基转换和颠换,无碱基插入和缺失发生,碱基转换的频率高于颠换的频率;在核苷酸水平上的多数碱基替换都是同义替换;序列间单碱基变异位点大多出现在同一位点,多发生在密码子第3位,其次是第1位,最少发生在第2位,符合分子进化的中性学说.HSL基因外显子Ⅰ部分核苷酸序列进行多序列对位排列构建的各物种间分子系统进化树结果表明,普通牛和瘤牛首先聚为一类,再分别与牦牛、水牛、猪、人聚类,最后与大鼠、小鼠聚为一类.该聚类结果与动物学上的分类结果一致,表明HSL基因外显子Ⅰ部分核苷酸序列适合于构建物种间分子系统进化树.研究表明,牦牛、普通牛和瘤牛3个物种间的遗传距离大小相近,牦牛和水牛间的遗传距离与普通牛、瘤牛和水牛间的遗传距离大小相当.牦牛、普通牛和瘤牛3个物种间的遗传距离远小于它们各自与水牛这一物种的遗传距离,它们三者之间的亲缘关系也相对于它们各自与水牛间的亲缘关系都较近,故将牦牛、普通牛和瘤牛划分在同一个属--牛属(Bos)更为合理.
재대우과중4충동물즉모우、류우、보통우화수우HSL기인외현자Ⅰ부분핵감산서렬진행측정적기출상,여GenBank중기타물충상응기인핵감산서렬、안기산서렬진행료비대분석,병구건료모우여기타물충간분자계통진화수.결과표명:모우여보통우、류우、수우、저、인、소서、대서7개물충HSL기인외현자Ⅰ부분핵감산서렬간보수성교고,동원성대소의차위99.8%、99.6%、97.4%、90.6%、88.4%、83.5%、82.3%.상응안기산서렬간보수성경고,동원성분별위100%、100%、98.2%、94.0%、92.2%、89.8%、89.8%.모우여각물충해기인부분핵감산서렬간감기변이류형주요표현위감기전환화전환,무감기삽입화결실발생,감기전환적빈솔고우전환적빈솔;재핵감산수평상적다수감기체환도시동의체환;서렬간단감기변이위점대다출현재동일위점,다발생재밀마자제3위,기차시제1위,최소발생재제2위,부합분자진화적중성학설.HSL기인외현자Ⅰ부분핵감산서렬진행다서렬대위배렬구건적각물충간분자계통진화수결과표명,보통우화류우수선취위일류,재분별여모우、수우、저、인취류,최후여대서、소서취위일류.해취류결과여동물학상적분류결과일치,표명HSL기인외현자Ⅰ부분핵감산서렬괄합우구건물충간분자계통진화수.연구표명,모우、보통우화류우3개물충간적유전거리대소상근,모우화수우간적유전거리여보통우、류우화수우간적유전거리대소상당.모우、보통우화류우3개물충간적유전거리원소우타문각자여수우저일물충적유전거리,타문삼자지간적친연관계야상대우타문각자여수우간적친연관계도교근,고장모우、보통우화류우화분재동일개속--우속(Bos)경위합리.
The partial sequences of exon Ⅰ of hormone-sensitive lipase (HSL) genes in yak (Bos grunniens), cattle (Bos taurus),zebu (Bos indicus), and buffalo (Bubalus bubalis) were analyzed.Comparisons of these sequences and the deduced amino acid sequences with the homologous HSL gene and protein sequences in other mammalian species including pig (Sus scrofa), human(Homo sapiens), mouse (Mus musculus), and rat (Rattus sp.) retrieved from the GenBank were carried out and finally a phylogenetic tree was constructed using the partial DNA sequences of the HSL genes in all species.The results showed that the homologies of the partial exon Ⅰ sequences of the HSL genes between yak and cattle, zebu, buffalo, pig, human, mouse, and rat were as high as99.8%, 99.6%, 97.4%, 90.6%, 88.4%, 83.5%, and 82.3%, respectively.This was accompanied by highly homologous amino acid sequences of the HSLs: 100%, 100%, 98.2%, 94.0%, 92.2%, 89.8%, and 89.8% identity, respectively.There are more transitions,less transversions, and no insertion or deletion in variable nucleotides of the HSL genes between the yak and other species.The majority of the variable mutations was synonymous and was found most frequently at the third codon, followed by the first and second codons, a finding that was in accordance with the neutralism hypothesis for molecular evolution.In the phylogenetic tree,the cattle and zebu were clustered together first, followed by the yak, buffalo, pig, human, mouse, and rat.This was in agreement with taxonomy suggesting that the partial sequences of exon Ⅰ of the HSL genes were useful in constructing the phylogenetic tree of mammalian species.Among the four species of Bovidae, genetic differentiation in the HSL genes between yak and buffalo is equivalent to that between buffalo and cattle and between buffalo and zebu.Furthermore, the genetic distances in the HSL genes are much smaller between yak, cattle, and zebu than those between each of the three species and the buffalo.Therefore, it is reasonable to consider yak as an independent species of the genus Bos.