MHC haplotype diversity in Icelandic horses determined by polymorphic microsatellites
Camille M Holmes1, Nathaniel Violette1, Donald Miller1
1Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
Genes and Immunity
|May 10, 2019
Summary
Icelandic horses exhibit exceptional major histocompatibility complex (MHC) diversity, with unique haplotypes and high heterozygosity. Intra-MHC recombination may drive this diversity in their disease-free environment.
Area of Science:
- Immunogenetics
- Animal Genetics
- Equine Science
Background:
- The Icelandic horse is a genetically isolated population with no new breed introductions since 1000 CE.
- Understanding the genetic diversity of the Major Histocompatibility Complex (MHC) is crucial for immune system function and disease resistance.
Purpose of the Study:
- To determine the diversity of MHC haplotypes in the Icelandic horse population.
- To investigate the potential role of intra-MHC recombination in generating novel MHC haplotypes.
Main Methods:
- Analysis of 156 Icelandic horses from two groups.
- Genotyping using a panel of 12 polymorphic intra-MHC microsatellites.
- Family-based analysis of 147 observed meioses.
Main Results:
- Identification of 79 unique MHC haplotypes, none previously described in other horse breeds.
- Discovery of one intra-MHC recombination event.
- Extremely high MHC heterozygosity with only one homozygote found in the studied population.
Conclusions:
- Icelandic horses possess exceptionally high MHC haplotype diversity and heterozygosity.
- The lack of common equine pathogens in Iceland suggests non-pathogen-driven forces maintain this diversity.
- Intra-MHC recombination is proposed as a significant mechanism for generating novel MHC haplotypes in this unique breed.
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