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First-Time Breeders Can Have Fun Learning About Coat Color Genetics While Health Testing
B reeding your own show dog for the first time is the next big leap after the dog show bug has bitten you. There are so many things to consider, like finding a mentor, researching pedigrees, selecting a stud dog for your brood bitch, learning about the health of your breed, conducting the rec- ommended health screenings and genetic tests, setting up your home to welcome your first litter, and finding loving homes for the puppies. When it comes to genetic testing, breeders can learn about canine traits like coat color in addition to the breed-specific health tests. With a comprehensive Embark for Breeders DNA Test Kit (which tests for health, traits, and COI), first-time breeders or those who have not used genetic testing before can test for health while also having fun learning about the genetics of coat color. Embark hopes this article—along with this handy infographic—will make coat color easier to understand. If you would like additional help, you can contact a mem- ber of the Embark team at breeders@embarkvet.com . To celebrate DNA Month this April, save $30 off your next Embark for Breeders DNA Test kit. Order using code RINGREADY at embarkvet.com/breeders . Offer ends May 31, 2021. WHAT EMBARK REPORTS FOR THE E, K, A, B, AND D LOCI: The E locus (MC1R) has 4 alleles which can be reported: Em, Eg, E, and e, and it has a hierarchical dominance pattern. Em (melanistic or dark mask) is at the top and is dominant to the other E alleles. This is the characteristic facial mask seen in the German Shepherd Dog and Pug. Eg (grizzle) is next in line and looks like the widow’s peak of the Afghan Hound. The physical visibility of the mask or grizzle is dependent on the genotypes at the K and A loci. For example, in order for grizzle to be seen phenotypically, a dog must also have the genotype kyky at the K locus and atat at the A locus. In theory, a dog could also be ata, however, the a allele has not been documented in breeds with visible grizzle. The E allele provides the ability to make eumelanin in the coat and is dominant to the e allele (recessive red). Dogs that are EE or Ee can produce dark (black, brown, blue, Isabella) hairs, but their distribution will be dependent on the genotypes at the K and A loci. Dogs that are ee (recessive red) will not produce any dark hairs regard- less of their genotype at the K, A, B, and D loci. (Interestingly, you can usually tell what their genotype is at the B and D loci by the color of their nose.) The shade of red of their coat can range from a deep copper like the Irish Setter, to yellow like a Lab- rador Retriever, to the white of the Samoyed. This variation in red color intensity is controlled by multiple genetic loci and has different genetic determinants in different breeds. Embark is working on defining the genetics behind red color intensity, and you can help by providing high-quality images of your ee dogs within their profiles. The two reported alleles at the K locus (CBD103) are KB and ky. Embark does not report brindle (sometimes abbreviated as Kbr), because currently there is insuf- ficient evidence supporting the genetics of brindle for Embark to accurately report. KB is dominant to ky . This means only one copy of KB is needed for the coat color to be expressed. We use the term dominant black for KB. If a dog has at least one KB allele, you can completely ignore the A locus regarding that dog’s phenotype. In a breeding animal, it may be important to know the A genotype, however. If a dog is kyky (and not ee), then the A locus will be expressed as follows:
134 | SHOWSIGHT MAGAZINE, APRIL 2021
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