Application of microsatellite DNA markers for the genetic identification of selected hybrid dog breeds

Abstract

The aim of the study was to assess the effectiveness of a microsatellite DNA analysis to genetically identify dog breeds and crossbreeds, using reference populations of purebred individuals and Bayesian clustering methods. The study was conducted based on 21 microsatellite markers (STR) that are recommended by the International Society for Animal Genetics (ISAG) for routine canine pedigree verification. The genetic diversity and population structure were assessed for 4 selected breeds: Golden Retriever, Bernese Mountain Dog, Poodle and Chinese Crested Dog. These reference populations were then used to analyse two case studies involving breed verification. Key genetic parameters were calculated, including the observed (HO) and expected heterozygosity (HE), degree of inbreeding (FIS) and the polymorphism information content (PIC). The probability of exclusion was estimated in cases of knowing the genotype of one of the parents (CPE1) and both parents (CPE2). A relatively high level of genetic diversity among the studied breeds, constituting reference populations, was found to be above 50% for HO and PIC, with no inbreeding. The probability of CPE1 and CPE2 was obtained at the level of 99% and 99.99%, respectively, which allowed the use of these markers for a parentage analysis. Bayesian clustering (STRUCTURE) and a Principal Coordinates Analysis (PCoA) were applied to assess the genetic structure and to identify the admixture in genotypes of the crossbred individuals. In both cases, the analyses successfully confirmed the breed’s pedigree or detected mixed ancestry, which was further supported by the parentage testing. The results confirm that the applied STR marker panel is suitable for breed identification and the detection of hybrid ancestries in dogs. While further research is needed to validate the method across a wider range of breeds, the study provides a valuable foundation for the development of DNA-based tests to support breed verification and the assessment of breed compositions in designer and hybrid dogs.