Half of 23 Belgian dog breeds has a compromised genetic diversity, as revealed by genealogical and molecular data analysis.

The genetic diversity in 23 dog breeds raised in Belgium was investigated using both genealogical analysis and microsatellite markers. Some of these breeds are native breeds, with only small populations maintained. Pedigree and molecular data, obtained from the Belgian kennel club, were used to calculate the inbreeding coefficients, realised effective population size as well as probabilities of gene origin and average observed heterozygosity. Inbreeding coefficients ranged from 0.8 to 44.7% and realised effective population size varied between 3.2 and 829.1, according to the used method and breed. Mean observed heterozygosity ranged from 0.47 to 0.73. Both pedigree and molecular methods reveal low genetic diversity and presence of bottlenecks, especially in native Belgian breeds with small population sizes. Furthermore, principal component analysis on the set of investigated diversity parameters revealed no groups of breeds that could be identified in which similar breeding strategies could be applied to maintain genetic diversity.