HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies and phylogenetic analysis of Bahraini population

Abstract

The origin of Arab-speaking population is classified according to their geographical location, ethnic background, and historical influx of nearby and distant populations. Data on HLA class I and class II loci in (Arabian Peninsula) Bahraini population are lacking. We analyzed HLA genetic profile of Bahrainis with neighboring communities, and with Levantines, North Africans, Sub-Saharans, Europeans, and Asians, using genetic distances, neighbor-joining dendrograms, correspondence and haplotype analysis. HLA class I and class II genotyping were done by high resolution PCR-SSP in 175 Bahraini subjects. In total, 19 HLA-A, 33 HLA-B, 15 HLA-C, 14 DRB1 and 7 DQB1 alleles were identified. The most common class I alleles were A*02:01:01 (18.3%), A*01:01:01(15.4%), B*35:01:02 (12.9%), C*12:01:01 (15.1%), and C*04:01:01 (14.9%), while DRB1*03:01:01 (18.0%), DQB1*02:01:01 (29.1%), and DQB1*05:01:01 (24.9%) were the most frequent class II alleles. Significant linkage disequilibrium was seen between all HLA loci pairs. DRB1*03:01:01-DQB1*02:01:01 (15.18%) was the most frequent two-locus haplotype. Significant negative Fnd values were observed, indicating balancing selection at studied loci. Bahrainis appear to be related to Western Mediterranean (North Africans, Iberians and French), but relatively distinct from Levantines (Palestinians, Lebanese, and Jordanians) and Sub-Saharans. This indicates limited genetic contribution of Levantine Arabs and Sub-Saharans to the Bahraini gene pool.