Genetic Coefficient of Inbreeding
Track the impact of inbreeding
Genetic coefficient of inbreeding (COI) is the most accurate method for measuring inbreeding. Unlike pedigree based COI calculations, genetic COI evaluates the actual pieces of DNA in your dog to identify which proportion traces back to inbreeding. Embark’s genetic COI can detect inbreeding in far more past generations, as well as better inform on strategic breeding crosses than typically expected from pedigree-based calculations.
Why does COI matter to breeding programs?
Many factors are considered when choosing which dogs to use in breeding programs including conformation, temperament, genetic disease mutations, and much more. Assessing the impact of inbreeding should be another factor.
Studies show that excessive inbreeding can have a profound impact on a dog’s health and lifespan. Many breeding programs utilize linebreeding and inbreeding as a means of maintaining breed characteristics and emphasizing desired traits. However, as inbreeding increases in a breed so do some negative effects, such as reduction of litter size, reduced fertility, decreased disease resistance, and failure to thrive in puppies.
Using COI to optimize breeding programs
Embark offers a unique service for breeders to evaluate the expected litter outcomes for any two potential mating dogs that have used an Embark DNA test for Breeders. This free service is offered to breeders that have used an Embark for Breeders Test and includes the following analysis:
- The expected genetic COI of the litter, providing easy comparison to that of the mating dogs’ COI score to assess if the degree of inbreeding in the line will decline as a result of the mating
- The expected occurrence of genetic disease mutations of the proposed litter
- The expected occurrence of relevant physical traits of the proposed litter
Depending on their breed, breeders can utilize this service through a match making tool available with their DNA test results, or by contacting Embark’s customer service team
Differences between Genetic COI and Pedigree-based COI
Breeders have traditionally relied on the pedigree evaluation method to measure the coefficient of inbreeding, which assumes that each parent passes on 50% of their DNA evenly across each chromosome. In practice, however, the percentage of an individual’s own parent’s DNA transmitted to their offspring varies due to recombination. Over many generations these differences in inheritance can add up to a significant variation between the dog’s actual COI and the estimated COI from the parentage method (genetic based COI results can vary from pedigree-based COI by as much as 70%).
The pedigree-based method also assumes that founder dogs in a given pedigree are completely unrelated, though breed analyses show this is rarely the case. Additionally, the pedigree method requires the careful record-keeping of each litter across dozens of generations, and errors can occur.
While keeping detailed pedigree records is certainly important, utilizing a genetic COI is an easier and more accurate means of assessing inbreeding impact and long term health within breeding programs.
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