Why are some Paints loud-colored tobianos and others just have a small spot or two?
The American Paint Horse Association (APHA) is working with the University of Florida Brooks Equine Genetics Lab to better understand the genetics of Paint Horse coloration, the association announced.
The Fort Worth, Texas-based APHA has provided laboratory director Dr. Samantha Brooks, an APHA member, and her team with research regarding genotypes, phenotypes and registration classification, the Paint Horse Journal reported. The team will study the genetics behind Paint color patterns, average distribution rates of white markings based on genomics and the likelihood a horse might qualify for regular registry status based on his or her genetic makeup.
As of November 2017, the group had analyzed 431 horses. Those animals had 27 genetic combinations, ranging from no pattern genes present to single copies of pattern genes such as Frame Overo or Sabino 1, to homozygous horses or those carrying multiple pattern geneses.
According to the APHA, the more spotting alleles present in a horse, the more likely that horse will be classified as a Regular Registry individual.
Some of the horses – eight regular registry and 56 solid Paints – had no spotting genes.
These regular registry horses might have “lucky spots,” resulting from favorable stocking/face markings or incomplete melanocyte migration during development that create white spots meeting the APHA’s registration guidelines without a specific pattern gene as the root cause.
- one spotting gene present: 147 regular registry v. 37 solid Paint-breds
- two spotting genes present: 141 regular registry v. six solid Paint-breds
- three spotting genes present: 30 regular registry v. zero solid Paint-breds
- four spotting genes present: one regular registry v. zero solid Paint-breds
Of the study’s 99 solid Paint-bred registry horses, nearly half of them carried at least one Paint pattern gene.
“Recognizing the value in solid Paints is an important concept,” Brooks said. “Of the solid Paint-breds, almost half of them have a valuable spotting allele. Half of your solid Paint-breds have value as breeding stock based on their spotting patterns alone, not taking into consideration things like conformation, performance or popular pedigrees. Solid Paint-bred does not necessarily mean no spotting genes.”
The APHA will continue to provide additional research samples to Brooks for continued study. Three horses from the original data set have inspired the search for a new spotting pattern – they each have extensive white markings, but test negative for the known pattern genes. Identifying the genetics behind rabicano – an extensive roaning-type pattern – is also in the works.
Further initiatives that could stem from this information might include a digital application or program designed to help breeders predict the likelihood of getting a regular registry foal based on the genotypes of the sire and dam. A spin-off project might include research into a computer-based photo analysis system that helps classify horses’ registry type for associations like the APHA or creation of registration rules by APHA directors that consider a horse’s genetic makeup more completely to determine registry status.
“The quality and pattern of a foal is only determined by the DNA passed to that foal from the dam and the sire,” Brooks said. “By examining the DNA directly, breeders will be able to accurately gauge the value of their breeding stock. Genetic tools give breeders the power to optimize their breeding plans in order to maximize color and quality, leading to better profitability in the end.”
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