Understanding How to Measure Genetic Diversity is Important for Curly Coated Retriever Breeders.
Updated: Aug 30, 2018
When breeders of a rare breed try to increase the genetic diversity of their stock, it is important to use tools which accurately measure diversity.
Several curly coated retriever breeders have developed an interest in increasing the genetic diversity of the breed--an effort I wholeheartedly agree with. But some of these efforts are actually contributing to the loss of diversity because of confusion or a misunderstanding of how to assess diversity.
One breeder extolled the virtues of a curly coated as a important breed contributor because the dog has no common ancestors in his first three generations. Unfortunately, having no common ancestors in the first three generations does not indicate great genetic diversity. What a shame if other breeders or puppy buyers believe a curly with no common ancestors in the first three generations is somehow more genetically diverse than the rest of the breed. This type of misunderstanding could lead to more inbreeding, not less.
First of all, truly accurate genetic diversity cannot be measured by breeding coefficients. An inbreeding coefficient is merely a probability chart predicting the influence of each ancestor on a particular litter. The most accurate measure of genetic diversity right now involves DNA testing.
But let's indulge this breeder referenced above who uses a THREE generation pedigree as a basis of claiming a dog is genetically diverse. Wow--pretty sure most curly coated retriever breeders/fanciers will immediately understand the fallacy of using THREE generations to measure a dog's genetic diversity.
Let's examine the pedigree of one of the most famous and revered curly coated retrievers in history--Darelyn Rifleman. This dog is an ancestor of probably 99.9999 percent of every living curly today. I believe there are only about 7 living dogs and maybe 2 dogs with frozen semen who don't have this dog in their pedigree. (I could be wrong--if you have a curly coated retriever who doesn't have this dog in the pedigree, I would LOVE to hear from you.)
So let's look at "Manny's" 4 generation pedigree.
Look at the notation in the top right corner "Coefficient of inbreeding." Rifleman only has an inbreeding coefficient of 3.52%, which is excellent for a rare breed!
But now let's look at TEN generations of Manny's pedigree which is the minimum number of generations most geneticists recommend for calculating inbreeding coefficients.