Genetic variation and gene conversions within the bovine NK-lysin gene family

In contrast to a single copy of the NK-lysin gene in humans and many other mammals, we previously identified a family of four expressed NK-lysin genes arising by tandem duplications on cattle chromosome 11. Here, we report two genetic variants in the bovine NK-lysin complex with potential importance in the bovine innate immune system. The first one is a 9-bp deletion causing a three-amino-acid deletion in the pro-region of the NK1 gene product. The second is a deletion of NK2B in some Holstein cattle, resulting in copy number variation that is in disequilibrium with a SNP from the bovine 770K HD SNP array. We also show evidence for gene conversions within the three new NK2 genes, which at least partially accounts for their high degree of sequence identity.