Analysis of the equine peripheral blood transcriptome in the context of blood group variability.

RNA-seq analysis of 100 horses representing various breeds was conducted to investigate the molecular background of the equine blood group K. A transcriptome-wide association study (TWAS) of detected variants and serological blood-typing results identified a significant region on ECA2. A closer examination of this region pinpointed the glycophorin A (GYPA) gene as the most promising positional and functional candidate. Re-sequencing of the entire coding sequence of GYPA revealed a dinucleotide missense variant (c.145_146GA>AT; p.Asp49Ile), which was found to be fully associated with the serological results of K blood group typing.