by Carol Beuchat PhD
For those that asked about other examples of the application of population genetics analyses to dog breeds, here is another excellent paper that does this for two uncommon breeds, Nova Scotia Duck Tolling Retrievers and Lancashire Heelers. Like Oliehoek did in his study of Icelandic Sheepdogs (see the previous posts beginning here), Maki gathered up the pedigree data for essentially the entire worldwide registered populations of these breeds back to founders – a total of almost 29,000 dogs for Tollers, and nearly 5,000 for Heelers.
For the Tollers, there were 22 original founder dogs and for Heelers 155 founders, but in both breeds only a fraction of the offspring were bred (13% of Tollers were bred, 25% of Heelers). As a consequence, the average inbreeding coefficient of Tollers rose rapidly right at the start and reached 25% within 15 years of founding. It has fluctuated slightly since, reaching as high as 30% at one point. The average degree of inbreeding increased more slowly in the Heelers (remember, there were more founders, which will slow the rate of inbreeding) and appeared to have stabilized by the time of the study at about 10%.
For those that asked about other examples of the application of population genetics analyses to dog breeds, here is another excellent paper that does this for two uncommon breeds, Nova Scotia Duck Tolling Retrievers and Lancashire Heelers. Like Oliehoek did in his study of Icelandic Sheepdogs (see the previous posts beginning here), Maki gathered up the pedigree data for essentially the entire worldwide registered populations of these breeds back to founders – a total of almost 29,000 dogs for Tollers, and nearly 5,000 for Heelers.
For the Tollers, there were 22 original founder dogs and for Heelers 155 founders, but in both breeds only a fraction of the offspring were bred (13% of Tollers were bred, 25% of Heelers). As a consequence, the average inbreeding coefficient of Tollers rose rapidly right at the start and reached 25% within 15 years of founding. It has fluctuated slightly since, reaching as high as 30% at one point. The average degree of inbreeding increased more slowly in the Heelers (remember, there were more founders, which will slow the rate of inbreeding) and appeared to have stabilized by the time of the study at about 10%.
