Haplotype analysis of non-HLA immunogenetic loci in Turkish and worldwide populations.

Immunogenes (i.e., genes related to the immune system and its functions) are involved in the predisposition to numerous traits and their variation contributes to the phenotypic variability observed among human groups. Turkish population presents particular genetic features since its genetic pool is an admixture of European, Middle-Eastern, and Central Asian ancestries. Here, we analyzed the haplotype structure of four immunogenetic loci (i.e., ADAM33; IL13-IL4; IL4R; MS4A2) in 482 subjects from five different regions of Turkey. Genotyping was performed using KASP technology. Turkish data were compared with the haplotype information available from the 1000 Genomes Project Phase 3 (26 human populations from 5 ancestry groups). We did not observe significant differences among Turkish groups. Comparing other ancestries, we identified haplotype similarity of Turkish subjects with European populations in IL13-IL4, IL4R, and ADAM33 loci; and with central Asians in MS4A2 region. Considering loci displaying Turkish-European haplotype similarity (i.e., IL13-IL4, IL4R, and ADAM33), we observed differences between Turkish subjects and northern/western Europeans. Conversely, no significant difference was determined in MS4A2 between Turkish and central Asian populations. Finally, we assessed the haplotypes responsible for the differences between Turkish and European samples and the potential functional effects on the immunogenetic loci investigated.