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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Cell Wall Biology and Utilization Research » Research » Publications at this Location » Publication #339322

Title: Comparison of the cattle leukocyte receptor complex with related livestock species

item SCHWARTZ, JOHN - The Pirbright Institute
item HEIMEIER, DOROTHEA - The Pirbright Institute
item Bickhart, Derek
item Smith, Timothy - Tim
item MEDRANO, JUAN - University Of California
item HAMMOND, JOHN - The Pirbright Institute

Submitted to: International Society for Animal Genetics (ISAG)
Publication Type: Abstract Only
Publication Acceptance Date: 4/14/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The natural killer (NK) cell receptor gene complexes are highly variable between species, and their repetitive nature makes genomic assembly and characterization problematic. As a result, most reference genome assemblies are heavily fragmented and/or misassembled over these regions. However, new long-read sequencing and assembly strategies promise to overcome these complications. Thus, by using new genome assemblies for cattle, goats (divergence from cattle ~30 mya), and pigs (divergence from cattle and goats ~60 mya), we have greatly improved the assembly and characterization of NK cell receptor complexes. In particular, the leukocyte receptor complex (LRC) is highly variable in gene content between these three species. In cattle, for which more published information is available, we identified three distinct haplotypes of killer immunoglobulin-like receptors (KIR) which vary greatly in their gene content. In addition, cattle have greatly expanded their leukocyte immunoglobulin-like receptor (LILR) content in comparison to goats. Furthermore, in the current pig reference assembly (Sscrofa10.2), we identified a large 280-kb sequence gap which in the new assembly contains a large number of novel LILR genes. We also identified a third group of novel, yet closely related immunoglobulin genes downstream from the KIR region in all three species. These novel genes vary in gene number between species, are highly similar to one another, and encode both activating and inhibitory receptors. The large amount of variation between species that we observed is consistent with a quickly evolving LRC under strong selection pressures. These observations are a necessary step toward understanding the NK cell receptor repertoire and will help inform future studies investigating immune response variation in these important species.