Pure wild forest reindeer (Rangifer tarandus fennicus) or hybrids? A whole-genome sequencing approach to solve the taxonomical status

In Finland, the geographic distribution of semi-domestic reindeer (Rangifer tarandus tarandus) and wild forest reindeer (Rangifer tarandus fennicus) partly overlap in the vicinity of the southern border of the reindeer herding area. Hybridisation of these two subspecies is one of the major threats for the wild forest reindeer population, and the implemented conservation program targets preventing the crossbreeding of these reindeer. In this paper, we resequenced genomes of four Rangifer tarandus individuals with unknown taxonomical status and investigated their ancestries by comparing the genomic data with the existing resequenced data of the Finnish semi-domestic reindeer and Finnish wild forest reindeer. The genetic relationship investigations suggest that the four individuals were pure forest reindeer animals. Our study provides critical knowledge for practical conservation actions of wild forest reindeer in the reintroduction project, for which it is essential to recognise each individuals origin. In the future, it will also offer novel insights into the spread of native wild forest reindeer to new geographic regions in Finland. For subsequent studies, additional resequenced genomic data of Rangifer individuals will be needed to develop an ancestry information marker panel of single nucleotide polymorphisms for rapid and cost-effective identification of hybrid individuals of semi-domestic reindeer and wild forest reindeer.