鸡MHC-B区域内复合微卫星LEI0258位点等位基因的序列变异

在对15个样品鸡MHC-B区域内复合微卫星位点LEI0258的等位基因进行基因型分析的基础上,进一步开展了等位基因PCR产物的直接测序或克隆测序,并将获得的序列与GenBank中的18条同源序列作了比较.结果表明:LEI0258位点等位基因片段大小分别为247bp、249bp、307bp、357bp、369bp、381bp、393bp或443bp的等位基因具有不同的DNA序列或结构;上、下游共有3个in/dels和7个SNPs;由12bp和13bp组成的重复单元中也存在一定的变异,其中,HRJ23中一个13bp的重复单元由标准的"CTATGTCTTCTTT"变为"CTATATCTTCTTT",HRJ5和JT01中各有一个12bp的重复单元由标准的"CTTTCCTTCTTT"变为"CTTC-CCTTCTTT",而HRJ5、HRJ15和P22中也各有一个12bp的重复单元由标准的"CTTTCCTTCTTT"变为"CTTTTCTTCTTT".

Sequence variations in alleles at the compound microsatellite locus LEI0258 within chicken MHC-B region

To investigate the sequence variation in alleles at the compound microsatellite locus LEI0258 located within chicken MHC-B region,15 samples were firstly genotyped for their allelic sizes and then sequenced for either their direct PCR products or their cloned PCR products.The sequences were further compared against 23 homologous sequences retrieved from GenBank.The results showed that alleles sharing the same sizes of 247 bp,249 bp,307 bp,357 bp,369 bp,381 bp,393 bp or 443 bp may have different DNA sequences and/or structures.A total of three in/dels and seven SNPs were found in their flanking sequences.There were also variations within the typical compound repeat units that were made up of 12 bp of "CTTTCCTTCTTT" and 13 bp of "CTATGTCTTCTTT",respectively.For example,one of the 13 bp repeats in sample HRJ23 changed into "CTATATCTTCTTT",one of the 12 bp repeats changed into "CTTCCCTTCTTT" in samples HRJ5 and JT01 and into "CTTTTCTTCTTT" in samples HRJ5,HRJ15 and P22.