Analysis of Polymorphism Provides Relevant Information on Centromeric Gene Content.

Four killer cell Ig-like receptor () genes, collectively referred to as framework genes, characterize almost all haplotypes. In particular, and mark the ends of the locus, whereas and are located in the central part. A recombination hot spot, mapped between and , splits the haplotypes into two regions: a centromeric (Cen) region (spanning from to ) and a telomeric region (from to ), both varying in gene content. In this study, we analyzed polymorphism in a cohort of 316 healthy, unrelated individuals. To this aim, we divided alleles into two groups by the use of a sequence-specific primer- PCR approach. Our data clearly indicated that alleles present on haplotypes carrying Cen-A or Cen-B1 regions differ from those having Cen-B2 motifs. Few donors (∼3%) made exceptions, and they were all, except one, characterized by uncommon haplotypes, including either deletions or duplications. Consequently, as is present in Cen-A and Cen-B1 regions but absent in Cen-B2 regions, we demonstrated that polymorphism might represent a suitable marker for gene copy number analysis. Moreover, because Cen-B1 and Cen-B2 regions are characterized by different alleles, we showed that polymorphism analysis also provides information to dissect between Cen-B1/Cen-B1 and Cen-B1/Cen-B2 donors. Taken together, our data suggest that the analysis of polymorphism should be included in repertoire evaluation.