Polymorphism, recombination, and linkage disequilibrium within the HLA class II region.

摘要: Thirty-nine CEPH (Centre d'Etude du Polymorphisme Humain) families, comprised of 502 individuals, have been typed for the HLA class II genes DRB1, DQA1, DQB1, and DPB1 using nonradioactive sequence-specific oligonucleotide probes to analyze polymerase chain reaction amplified DNA. This population, which consists 266 independent chromosomes, contains 27 7 12 17 alleles. Analysis distribution allele frequencies homozygosity statistic, gives an indication past selection pressures, suggests that balancing has acted on DQB1 loci. The alleles, however, a different evolutionary past. Family data permits estimation recombination rates unambiguous assignment haplotypes. No recombinants were found between DQB1; detected DPB1, resulting in estimated fraction greater than or equal 0.008 +/- 0.004. Only 33 distinct DRB1-DQA1-DQB1 haplotypes this population illustrates extreme nonrandom haplotypic association alleles at these A few are unusual (previously unreported) Caucasian most likely result from events DR DQ subregions. Examination disequilibrium across region available serologic HLA-A HLA-B types samples shows global loci declines with fraction, approaching statistic nonsignificance distant interval, HLA-DP.DR-DQ linkage B noted and, finally, origin certain is addressed.