Genetic diversity is the variation of genetic material in a population. Breeds of dogs have a natural limitation of their specific population which makes them a specific breed, but the variation can be further limited by a number of differing practices.
Generally low genetic diversity means there are a smaller gene pool, and this can have impact on the overall health of a breed. Inbreeding (breeding of close relatives) can reduce the gene pool as there is increased likelihood that the parents share common genetic material, for this reason the Kennel Club prohibit matings of very closely related individuals preventing the mating of
- father and daughter
- mother and son
- brother and sister
(Note in UK marriage is permitted between first cousins, which equates to inbreeding level of 12.5%)
The Coefficient of Inbreeding (COI) is a measurement used to calculate the probability that two copies of a gene variant have been inherited from an ancestor common to both the mother and the father. It is based on the assumption that when inheriting 50% of the DNA material from the sire and 50% from the dam, the DNA has been passed equally from the Sire’s parents and the Dam’s parents, but in nature this is not necessarily what does happen. As DNA testing is now more affordable it is now possible to not only estimate the COI based on the pedigree (and laws of probability), but an accurate measure of the level of inbreeding can be obtained based on the actual DNA material present in any given dog.
The Kennel Club’s health test Results finder will give a COI calculation based on pedigrees recorded at the KC, but unfortunately for Finnish Lapphunds this is not always accurate, as when dogs/bitches are imported to UK, only three generations of pedigree are required – and COI calculations are generally calculated on 5-12 generations. We have included the COI (to 6 generations) with the record of every litter born in UK, see below..
Popular Sire Syndome
Popular Sire syndrome will also impact genetic diversity, with some sires being used in matings frequently and over a short time frame, their DNA then contributes to a high proportion of the population. The effect is two fold, should they develop a condition that is inherited later in life – then the “spread” of such deleterious genes can be potentially devastating. Plus in subsequent generations the chances of mating parters sharing the same genetic materials increased as they become common ancestors and the COI is affected.
In Finland the PEVISA scheme aims to reduce the impact of the popular sire syndrome with sires being limited to producing a maximum of 20 puppies before they reach the age of 5 Years old, and a maximum of 70 puppies in their lifetime. These limits applying in a country where there around 1200-1500 puppies born a year. There are no such limits in the UK and so we are reliant on stud dog owners to considering the impact when agreeing to matings in a country where only 50 to 90 puppies are born a year.
The Kennel Club provide useful information on how to manage and maintain genetic diversity and understanding Canine genetics
Embark are one of the DNA laboratories that provide actual COI calculations and explains why pedigree COI are not as accurate as the measure of the DNA material
The first UK litter was born in 1991, and at the end of 2022 there have been a total of 288* litters totaling 1349 puppies, average litter size being 4.7 puppies (range 1 to 9)
* Two litters are dual sired, meaning that on each occasion one litter was born to the dam, but the puppies were by two different sires.