Immunoglobulin CH gene family in hominoids and its evolutionary history.
The organization of the human immunoglobulin CH gene suggests that a gene duplication involving the C gamma-C gamma-C epsilon-C alpha region has occurred during evolution. We previously showed that both chimpanzee and gorilla have two 5'-C epsilon-C alpha-3', as in human, and that orangutan, gibbon, and Old World monkeys have one C epsilon gene and one, two, and one C alpha gene(s), respectively. In addition to these clustered CH genes, there is one processed C epsilon pseudogene in each species. The present study revealed that orangutan and crab-eating macaque (an Old World monkey) both have one 5'-C epsilon-C alpha-3' and that gibbon has two 5'-C epsilon-C alpha-3', one C epsilon gene of which is completely deleted. By Southern analysis, the number of C gamma genes in all the nonhuman hominoids was estimated to be four to five, as in human, in comparison with two for crab-eating macaque. The C mu and C delta genes were estimated to be present as single copies in both hominoids and crab-eating macaque. Furthermore, it was proved that there are two copies of the C epsilon 5'-flanking region in both the orangutan and the gibbon genomes. These results show that gene duplication including the C gamma-C gamma-C epsilon-C alpha genes occurred in the common ancestor of hominoids and that subsequent deletion of the C epsilon gene (in orangutan, including one of the C alpha genes) occurred independently in each hominoid species.
Kawamura
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Department of Anthropology, Faculty of Science, University of Tokyo, Japan.
Ueda
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D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D015139:Blotting, Southern; D005803:Genes, Immunoglobulin; D006071:Gorilla gorilla / Q000235:genetics; D000882:Haplorhini / Q000235:genetics* / Q000276:immunology; D006801:Humans; D006922:Hylobates / Q000235:genetics; D007127:Immunoglobulin Constant Regions / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D008252:Macaca fascicularis / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D002679:Pan troglodytes / Q000235:genetics; D011148:Pongo pygmaeus / Q000235:genetics; D011544:Pseudogenes / Q000235:genetics
D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains