The Canine Diversity Project

Inbreeding and Diversity

by John Armstrong

Disclaimer

This is a story about Standard Poodles. In the Poodle, we are fortunate to have a breed with ancient and diverse origins. They are intelligent and versatile, and a recent German study has suggested that they are among the longest lived. My own study, though not complete, suggests that a Standard Poodle should live 14 years or more, given reasonable luck, and a Miniature about 2 years longer. (The averages are actually closer to 12 and 14 years, respectively.)

I would like to believe that you can have healthy, long-lived, championship-quality dogs in any breed. However, this may be a function of their inherent diversity. Many breeds have been established with a much more limited number of founders and, therefore, may never have included the best alleles for certain genes, or may have lost them as a result of random events.

Is Inbreeding Necessary?

Many breeders still cling to the idea that inbreeding is the only route to success, and that they can use it as a tool to identify and weed out genetic problems in their line. They will cite the success of certain breeders who inbred extensively, unaware (or conveniently ignoring) that the most successful litters from these kennels were often the least inbred. They also seem to be unaware that many studies on a wide variety of species have demonstrated that highly inbred individuals frequently live shorter lives and have fewer progeny. This is called inbreeding depression.

Inbreeding depression results, in part, from the bringing together of deleterious recessive alleles inherited via both parents from a common ancestor. In humans, where genetic diseases of this type are relatively rare, the frequency of affected individuals is often higher in small populations that are culturally or geographically isolated. In dogs, man has created similar isolated populations by restricting genetic exchange between pure breeds. However, given a sufficiently large and diverse group of founders, there is no reason why the average purebred should not lead a long, healthy life - if responsibly bred.

This article is cut as we do not know the Poodle - breeding - lines and names mentioned; but the article in generally applies to EVERY BREED - for complete article pls. visit the website www.optigen.com