期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：17
页码：9710-9715
DOI：10.1073/pnas.96.17.9710
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The Ig heavy chain variable region (VH) genes encode the antigen-binding regions of antibodies. The rabbit genome contains more than 100 VH genes, but only one (VH1) is preferentially used in the VDJ gene rearrangement. Three highly divergent alleles occur at this VH1 locus in most rabbit populations. These three VH alleles are also present in snowshoe hare populations, indicating that the polymorphism of the VH1 alleles is trans-specific. Here we report the results of a phylogenetic analysis of rabbit Ig germ-line VH genes (alleles) together with VH genes from humans and mice. We have found that all rabbit VH genes belong to one mammalian VH group (group C), which also includes various human and mouse VH genes. Using the rate of nucleotide substitution obtained from human and mouse VH sequences, we have estimated that the VH1 polymorphism in the rabbit lineage has been maintained for about 50 million years. This extremely long persistence of VH1 polymorphism is apparently caused by overdominant selection, though the real mechanism is unclear.
