Fig. 1.

Pairwise linkage disequilibrium between the presence or absence of 13 KIR genes. Lewontin’s pairwise standardized metrics describe linkage disequilibrium (LD) between all KIR genes but KIR3DL2 and KIR3DL3 which were thought to be always present. KIR genes are considered at the structural variation level (the presence or absence level; copy number variant). Computations were double-checked using Haploview software (a SNP-oriented software) as well as the combined use of Gold software for graphical display and Stata ver. 10.0 SE for computing the LD metrics. KIR3DL1 and KIR3DS1 are considered as two different genes. The physical gene position is a consensus map, and another order may better reflect the reality of a given haplotype. Although LD computations do not use the physical positions of the genes and their alleles, LD measures are not necessarily independent of gene order. For example, this is the case when one considers the possibility of 2DS3 and 2DS5 being present on either side or both sides of 2DL4