Is a potential regulatory region in the vicinity of EDN3 linked to the performance in Standardbred horses?

Sammanfattning: Standardbred horses (SBs) are used in harness racing. Their common breeding history with Coldblooded trotters (CBTs) led us to the hypothesis, that the same region associated with race performance in CBTs, may be linked to the performance of SBs as well. EDN3 SNP (g.22:45748491C>T), was found to be associated (p<0.05) with performance traits in CBTs (Fegraeus, 2017). EDN3 SNP has a high frequency of the T-allele in breeds related to races and to the high performance (Fegraeus, 2017). EDN3 SNP is located in the vicinity of endothelin-3 (EDN3) gene. Protein endothelin-3 (EDN3) is responsible for the development of the enteric nervous system and the melanin distribution in the foetus and it is involved in the blood regulation. Custom designed TaqMan SNP Genotyping Assays (Applied Biosystems StepOnePlusTM Instrument by Life Technologies) were used to genotype 550 SBs. Four hundred and fifty-seven genotypes were obtained and no statistically significant association between racing performance traits and genotype was found. Several associations (<0.05) between performance traits and other fixed effects – sex and year of birth - were found. The T-allele frequency of EDN3 SNP is 0.87 and the frequency of the C-allele is 0.13 for 467 genotyped SBs. Whole genome sequencing of homozygotes for the C-allele and the T-allele in trotter horses is planned. The follow-up research into the EDN3 vicinity is recommended.