Confirmed Hair Phenotypes of the Dog Breeds
8. Distribute the student sheet, “Confirmed Hair Genotypes,” which summarizes typical genotypes for each breed for a discussion with the class. Students may notice that in most cases, the breeds are homozygous for dominant traits. Based on phenotype, it is not possible to know if an individual has a single or both alleles for a trait that shows a dominant pattern of inheritance. However, because dog breeds have been selected over generations to “breed true,” most of the variant alleles have been eliminated over time. In other words, dogs with undesirable characteristics themselves (or whose offspring had undesirable characteristics) were not bred to produce additional offspring.
If students have questions about dog coat color, access one of the commercial dog testing websites to find a summary of the many different genes (and genetic tests) that are involved in determining color and patterns. Simply search, “dog coat color genetic testing.”
Much of the research on the Dog Genome has been led by Dr. Elaine Ostrander of the National Human Genome Research Institute of the National Institutes of Health. The following video summarizes much of the work to date on the dog genome, including examples used in this set of activities. In addition, she describes the relevance of studying dog genetics to understanding human diseases.
More information about the Dog Genome project can be found below.
- Bassett Hound and Kerry Blue Terrier © Bonzami Emmanuelle. Bichon frisé © Viorel Sima. Border Terrier and Golden Retriever © Eric Isselee. English Cocker Spaniel © Zdenek Maly. Havanese © Mdorottya. Licensed for use.
- Irish Water Spaniel © The Kennel Club. CC-BY-SA 2.0.
- Moreno, N. (2017) Complex Traits: Using Dogs as a Model for Modern Genetics. Baylor College of Medicine: Houston. ISBN: 978-1-994035-08-2.
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