The primary goal of the Thoroughbred industry is to breed and train superior
equine athletes capable of excelling on the racetrack. To date, research into the genetic
underpinnings of athletic ability has been limited in the horse. Advances in equine
genomics and the genetics of athletic performance in humans have opened up the
possibility of investigating this important trait in the Thoroughbred.
Initially, 46 candidate genes associated with human athletic performance were
mapped in the equine genome by radiation hybrid (RH) and fluorescent in situ
hybridization (FISH) mapping. RH data and later the draft equine genomic sequence
allowed us to identify microsatellites adjacent to these and other candidate genes (95 in
total). Additional microsatellites were added to increase genome coverage, producing a
final panel of 186 markers. All the potential markers were initially screened on a pool of
DNA for 16 Thoroughbreds to ensure they were polymorphic. The panel was genotyped
on 162 Thoroughbreds in total; Centimorgans (cM) between microsatellites were
determined with CRI-MAP. The animal?s athletic ability was estimated using career
winnings loge transformed to create a linear trait; unraced animals were treated as missing data. Linkage analysis was carried out using the MERLIN program, and
association analysis was carried out using the QTDT program. Appropriate thresholds
for statistical significance were determined by carrying out 1000 simulated genome
scans based on the structure of the original data. LOD scores above 1.54 met the criteria
of statistical significance (with a 5% chance of type I error). In the actual genome scan,
the marker L12.2 had the highest observed LOD score of 1.16 and p-value of 0.01 and
consequently was not significant; the association analysis also did not detect significant
association with performance on the track.
Given the complexity of the phenotype under investigation and the modest
sample size, the lack of linkage/association was not unexpected. Nevertheless, this study
has contributed to the RH and FISH maps of the equine genome. Additionally, the
development of the genome scanning panel for this study has provided useful
information on the most informative microsatellites for linkage or association studies in
the Thoroughbred.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-05-484 |
| Date | 16 January 2010 |
| Creators | Durkin, Keith W. |
| Contributors | Chowdhary, Bhanu P. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation |
| Format | application/pdf |
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