Fig. 1
From: Placing human gene families into their evolutionary context
Killer cell Ig-like receptor gene clusters display dramatic gene content variation. A Eleven gene content haplotypes for the human killer cell Ig-like receptor cluster within the leukocyte receptor complex adapted from Middleton and Gonzelez [28]. Framework killer cell Ig-like receptor genes are conserved across haplotypes (gray circles), whereas other genes (color-coded circles) are variably present across haplotypes. Additional haplotypic variation is achieved through a recombination hotspot between KIR3DP1 and KIR2DL4 [29] (small black circle). B Variation in the number and combination of killer cell Ig-like receptor genes within the leukocyte receptor complex in mammalian genomes [37,38,39,40]. Framework killer cell Ig-like receptor genes are conserved in primates (gray circles) and bounded by conserved flanking genes (black circles). The numbers of killer cell Ig-like receptors with predicted inhibitory (red) and activating (blue) functions vary between species. Additional gene content variation is observed for other gene families within the leukocyte receptor complex (e.g., leukocyte Ig-like receptors and leukocyte-associated Ig-like receptors). The figure is not to drawn scale; it is designed to highlight common sequences (ψ: pseudogene)