Characterisation of major histocompatibility complex class IIa haplotypes in an island sheep population

Research on St. Kilda's unmanaged Soay sheep population reveals limited diversity in major histocompatibility complex (MHC) class IIa haplotypes, with only eight distinct haplotypes identified across seven loci. The study, spanning 15 years, used a stepwise sequencing approach to characterize alleles at DRB1 and DQA/DQB loci in 118 sheep, confirming haplotype consistency in an additional 94 individuals. Evidence of historic positive selection was found at multiple loci, though no single locus captured the full extent of expressed variation. This work highlights the genetic structure of a unique island population, offering insights into immune diversity and evolutionary pressures in unmanaged ecosystems.

Dicks, K. L., Pemberton, J. M., & Ballingall, K. T. (2019). Characterisation of major histocompatibility complex class IIa haplotypes in an island sheep population. Immunogenetics, 71(5-6), 383–393. https://doi.org/10.1007/s00251-019-01109-w