Major histocompatibility complex haplotype diversity in Arab horses from Argentina

Abstract

Genetic diversity of the major histocompatibility complex (MHC) is essential for the antigen recognition and presentation during the immune response. Indirect MHC typing by microsatellites (STR) provides data on genetic diversity and population structure, and provides knowledge of selective and evolutionary processes. In order to characterize a sample of Arab horses, we identified MHC haplotypes based on three STRs (UM011, DRB2-STR2 and COR112) covering a region of ~1Mpb. Genomic DNA was extracted from blood and hair of 30 horses from five farms of the province of Buenos Aires. STRs were amplified with fluorescent primers and typed in an automated sequencer. Population and diversity parameters were estimated. Haplotype detection was performed by segregation analysis and with the PHASE program for reconstructing haplotypes. Of the 24 haplotypes identified, 12 were verified by segregation in the Stud Book pedigree records. Our results showed linkage with known equine leukocyte antigen (ELA) class II alleles. The number of haplotypes identified allowed to expand the estimates of diversity in the equine MHC. This methodology is a useful tool and an alternative approach to type MHC in horse lineages and immune-related population studies.