Diversity of killer cell immunoglobulin-like receptor genes in Southern Turkey

Killer cell immunoglobulin-like receptors (KIRs) are a family of inhibitory and activating receptors expressed by natural killer (NK) cells and regulate NK cells' activity. KIR genes are highly polymorphic markers, characterized by a wide diversity, and can therefore be considered as good population genetic markers. The aim of this study was to determine KIR gene frequencies, ratios of haplotypes and genotypes in Southern Turkey and also to compare the data with other worldwide populations studied previously. The study group consisted of 200 non-related individuals from Southern Turkey. The percentage of each KIR gene in the population group was determined by direct counting. Differences between populations in the distribution of each KIR gene and genotype profile were estimated by two-tailed Fisher Exact test. The most frequent non-framework KIR genes detected in Southern Turkey population were: KIR 2DL1 (97%), KIR 3DL1 (91%), KIR 2DS4 (92%) and the pseudogene 2DP1 (96%). Fourty different genotypes were found in 200 subjects and AA1 genotype was the most frequent (27%). Among 40 different genotypes, ten of these were described for the first time in this study and were added to the database ( http://www.allelefrequencies.net ) numerized as genotype ID from 400 to 409. Gene frequencies and found genotypes demonstrated similarity of Southern Turkey's KIR repertoire with the KIR repertoires of Middle East and European population. High variability seen in KIR genome in this region is thought to be formed as a result of migration and settlement of different civilizations in this region and heterogenity formed in time.