Esteves P J, Alves P C, Ferrand N, van der Loo W
Centro de Estudos de Ciência Animal, ICETA-UP, Vairão, Portugal.
Eur J Immunogenet. 2002 Dec;29(6):529-35. doi: 10.1046/j.1365-2370.2002.00355.x.
The European rabbit (Oryctolagus cuniculus) is the only species known to express only one subclass of gamma class immunoglobulin (IgG) antibodies. The rabbit IGHGCH2 (second domain of the gene region encoding the IgG heavy chain constant region) or e locus presents two serologically defined alleles, the e14 and e15 allotypes. These are correlated with amino acid variation at position 309, which is located within the target region of the neonatal FcRn receptor. The e14 and e15 markers were also observed in other lagomorph species. Population genetic research has indicated that polymorphism at this locus is sustained by selection. We present here the IGHGCH2 exon sequences for 12 species of rabbit and hare (genera Oryctolagus, Sylvilagus and Lepus). The inferred amino acid sequences reveal that, despite an overall sequence identity of 97%, five different residues can occur at position 309. As for Oryctolagus, the e15 allotype was always associated with the presence of an Ala309 codon. In all but one case, this codon defined an allotype-specific ThaI restriction site. The potential of PCR/ThaI restriction fragment length polymorphism (RFLP) analyses for studying IGHGCH2 variation within and between populations is emphasized.
欧洲兔（穴兔）是已知唯一仅表达γ类免疫球蛋白（IgG）抗体一个亚类的物种。兔IGHGCH2（编码IgG重链恒定区的基因区域的第二个结构域）或e位点呈现出两个血清学定义的等位基因，即e14和e15同种异型。这些与位于新生儿FcRn受体靶区域内第309位的氨基酸变异相关。在其他兔形目物种中也观察到了e14和e15标记。群体遗传学研究表明，该位点的多态性是由选择维持的。我们在此展示了12种兔和野兔（穴兔属、棉尾兔属和兔属）的IGHGCH2外显子序列。推断的氨基酸序列显示，尽管总体序列同一性为97%，但在第309位可出现五个不同的残基。对于穴兔来说，e15同种异型总是与Ala309密码子的存在相关。除了一个案例外，在所有情况下，该密码子都定义了一个同种异型特异性的ThaI限制性酶切位点。强调了PCR/ThaI限制性片段长度多态性（RFLP）分析在研究群体内部和群体之间IGHGCH2变异方面的潜力。
