Search

Athletic performance is influenced by a complex interplay among the environment and a suite of genes, which contributes to system-wide structure and function. In a panel of elite and non-elite Thoroughbred horses ( n = 148), we genotyped 68 SNPs in 17 putative exercise-relevant genes chosen from a genome scan for selection. We performed a series of case-control and quantitative association tests for relationships with racecourse performance. Thirteen SNPs in nine genes were significantly ( P < 0.05) associated with a performance phenotype. We selected five SNPs in four genes ( ACSS1, ACN9, COX4I1, PDK4) for validation in an independent sample set of elite and non-elite Thoroughbreds ( n = 130). Two SNPs in the PDK4 gene were validated ( P < 0.01) for associations with elite racing performance. When all samples were considered together ( n = 278), the PDK4_ 38973231 SNP was strongly associated ( P < 0.0005) with elite racing performance. Individuals with the A:A and A:G genotypes had a 16.2-16.6 lb advantage over G:G individuals in terms of handicap rating. Re-sequencing of the PDK4 gene and further genotyping will be required to identify the causative variant that is likely influencing exercise-induced variation in expression of the gene. Notwithstanding, this information may be employed as a marker for the selection of racehorses with the genetic potential for superior racing ability. [ABSTRACT FROM AUTHOR]

The recent completion of the horse genome and commercial availability of an equine SNP genotyping array has facilitated the mapping of disease genes. We report putative localization of the gene responsible for dwarfism, a trait in Friesian horses that is thought to have a recessive mode of inheritance, to a 2- MB region of chromosome 14 using just 10 affected animals and 10 controls. We successfully genotyped 34 429 SNPs that were tested for association with dwarfism using chi-square tests. The most significant SNP in our study, BIEC2-239376 ( P = 4.54 × 10, P = 7.74 × 10), is located close to a gene implicated in human dwarfism. Fine-mapping and resequencing analyses did not aid in further localization of the causative variant, and replication of our findings in independent sample sets will be necessary to confirm these results. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA (mtDNA) D-loop sequences (381 bp) from 100 thoroughbreds in 19 of the most common matrilineal female families were used to reconstruct a founder female population for the thoroughbred (∼1650–1750 AD). Seventeen haplotypes were found to have contributed to the 19 female lineages. In order to place the reconstructed founder population in wider historical context, we examined, using both single strand conformation polymorphism and direct sequence analysis, variation in a 343 bp mtDNA fragment in that population and 13 other horse populations of disparate provenance. Interpopulation diversity analyses revealed no significant difference in variation between the thoroughbred founder population and the 13 other diverse horse populations and suggested a non-random partitioning of diversity among geographically diverse horse populations. Within thoroughbreds, almost half of the female families, which are each considered from pedigrees to have matrilines converging to one of >30 historically recognized female ancestors, contained sequences which were inconsistent with common descent. Examination of the anomalies in the context of pedigree records suggests the majority might be best explained as confusion of mares at the foundation stages, although some could have some bearing on more recent (19th century – 1980) lineages. We have used this combination of molecular and historical information to identify some of the founder dams and to make new interpretations about the early history of the thoroughbred. [ABSTRACT FROM AUTHOR]

Studies the convenient detection of single nucleotide polymorphism haplotypes in the bovine growth hormone gene using amplification-created restriction sites. Characteristics of growth hormone; Amplification created restriction sites design, polymerase chain reaction and single nucleotide polymorphism genotyping; Haplotype network construction.