Multiplication of Mhc-DRB5 loci in the orangutan: implications for the evolution of DRB haplotypes

摘要: The β chain-encoding (B) class II genes of the primate major histocompatibility complex belong to several families. DRB family is distinguished by occurrence haplotype polymorphism—the existence multiple chromosomal forms differing in length, gene number, and combinations, each form occurring at an appreciable frequency population. Some haplotypes, or fragments thereof, are shared humans, chimpanzees, gorillas. In effort follow polymorphism further back time, we constructed contig maps two chromosomes present orangutan cell line CP81. Two types were found Popy-DRB5 Popy-DRB1*03, former copies one fragment haplotype, so that CP81 contains four complete DRB5 altogether. Since more closely related another than they other genes, must have arisen from a single ancestral copy duplications. At same however, haplotypes differ considerably their restriction enzyme sites presence Alu elements different positions, indicating been separated for length time exceeds lifespan species. Moreover, segment about 100 kilobase pairs between CP81-1 human HLA-DR2 haplotype. These findings indicate part may persisted 13 million years, which estimated human-orangutan divergence.