Genomic diversity and selection in the racing greyhound of Great Britain.

The greyhound has been strongly selected for competitive racing. Here, we present the first comprehensive population genomic analysis of racing greyhounds (n = 54) in the context of 14 other dog breeds (n = 352) using 473K single nucleotide polymorphism (SNP) genotypes. Inbreeding in the greyhound (FROH = 0.47) was higher than in most other breeds, reflecting positive selection for athletic traits but also raising concerns about potential health impacts. Although very long runs of homozygosity (ROH) were less common in the greyhound than in some breeds, large ROH islands suggest that selection for advantageous traits is relatively recent. Genomic regions under strong selection overlapped with ROH islands on CFA2, CFA4, CFA9, CFA10, CFA25 and CFA28 and contained candidate genes with marked allele frequency differences relative to other breeds. Notably, the strongest selection signal overlapped with the longest ROH island, encompassing the SLC46A3, POLR1D, FLT3, SLC7A1, MTUS2, LHFPL6, USPL1 and USP12 genes that have biological functions in vision, craniofacial morphology, neurological adaptability and skeletal, cardiac and muscle biology, implicating them in shaping the greyhound's morphological and athletic phenotype. These results provide insights into the selection pressures in the racing greyhound, identifying key genomic regions and candidate genes that may underlie racing capabilities, and importantly for animal welfare, provide a framework for managing inbreeding to optimize health and performance for future generations.