Robins are a common sight here in the Pacific Northwest. This robin lives in my backyard and he posed for a portrait this morning. He is easily identified as a robin because of his ‘robin like features’.
The scientific term for that outside appearance is ‘phenotype’. Probably this robin’s mom, thinks he has many unique qualities but for most of us, a robin is a robin and difficult to distinguish from any other.
On the genetic level, this robin is likely to have considerable genetic diversity. He inherited half his genes from his mother and half from his father. While it’s possible that his mother and father share some common ancestors, it’s not extremely likely, given the robin’s wide range and large open population. Genetic diversity is what makes both individuals and populations strong and resistant to disease.
A Schipperke is a Schipperke, because of its “Schipperke features” They are easily identifiable by those who know their features. People often stop to admire Ruby and ask me “Is that one of those Belgian Barge Dogs?”
But in contrast to the robin, my Ruby has much less diversity in her genome. Her COI is 22%, meaning 22% of the genes that she inherited from her mother and father came from an ancestor that was common to both of her parents.
Robins re-create their exterior characteristics quite well and still manage to maintain a considerable amount of genetic diversity. Schipperke breeders re-create the Schipperke phenotypes very well too, but have lost a considerable amount of genetic diversity. When dogs are spayed, neutered, or just not considered ‘good enough’ to breed, whatever genes those dogs had are lost to the population.
Robins breed quite well, at least they do in my yard. They lose eggs to predators like squirrels and only about 25% of baby robins survive to adulthood, but it’s safe to say that American robins are very successful. Any robin can mate, subject only to his attractiveness to others and his natural fitness. Robins have a wide range of choices.
Schipperkes are a closed population, where no new genes are introduced. The CKC and AKC studbooks are closed. Most Schipperkes are spayed and neutered and only a very small number are permitted to breed. Schipperkes’ mates are chosen for them, from a very, very small number of possibilities.
As fewer and fewer dogs are bred, their puppies become more and more similar genetically. The benefit that breeders appreciate is that they get a very reliable ‘type’ of Schipperke. The downside is that with greater similarity of genes, the likelihood of genetic diseases rises quickly.
Rebus, Ruby’s mate has also been genetically tested by Embark and his COI (Coefficient of inbreeding) is 32%. This means, that 32% of his genetic material is identical, coming from ancestors shared by both his father and his mother. So, if Ruby’s inbreeding number is 22% and Rebus’ inbreeding number is 32%, how can I be reducing the risk of genetic disease by breeding them together?
According to the National Wildlife Federation, “The American robin’s population is large and appears to be increasing. The bird has an extremely big range and has been successful at adapting to human alterations of its habitat.”
I think most of us who have tried to add a Schipperke to our lives have noticed that the Schipperke population is not large, nor does it have an extremely big range.
Maybe the robins know something we don’t…