Garber T L, Hughes A L, Letvin N L, Templeton J W, Watkins D I
Texas A & M University, Department of Veterinary Pathobiology, College Station 77843.
Immunogenetics. 1993;38(1):11-20. doi: 10.1007/BF00216385.
To explore genetic mechanisms responsible for major histocompatibility complex (MHC) class I evolution in the artiodactyls, we cloned and sequenced MHC class I cDNAs from a Bos taurus bull heterozygous for cattle MHC (BoLA) class I serological specificities w2 and w30. Four unique cDNAs were found, indicating the presence of at least two MHC class I loci. Analysis of these four cDNAs and all previously published BoLA cDNA sequences suggested that there may be three cattle MHC class I loci. Additionally, comparison of all of the BoLA class I cDNAs to MHC class I cDNAs of other artiodactyls showed that some of the BoLA class I cDNAs were more similar to certain sheep cDNAs than they were to other cattle cDNAs. These data indicate that each BoLA class I locus has evolved independently after an ancestral gene duplication event and that inter-locus segmental exchange or concerted evolution has not occurred rapidly enough to cause extensive divergence between the orthologous MHC class I loci of sheep and cattle.
为了探究偶蹄目动物主要组织相容性复合体（MHC）I类基因进化的遗传机制，我们从一头牛MHC（BoLA）I类血清学特异性w2和w30杂合的公牛中克隆并测序了MHC I类cDNA。我们发现了四个独特的cDNA，表明至少存在两个MHC I类基因座。对这四个cDNA以及所有先前发表的BoLA cDNA序列的分析表明，可能存在三个牛MHC I类基因座。此外，将所有BoLA I类cDNA与其他偶蹄目动物的MHC I类cDNA进行比较，结果显示，一些BoLA I类cDNA与某些绵羊cDNA的相似性高于与其他牛cDNA的相似性。这些数据表明，在祖先基因复制事件之后，每个BoLA I类基因座都独立进化了，并且基因座间的片段交换或协同进化发生得不够快，不足以导致绵羊和牛的直系同源MHC I类基因座之间出现广泛的分化。
