Veterinary session

The red deer (Cervus elaphus) is widespread throughout Europe and holds significant cultural, sacred, and economic value. On the IUCN Red List, it belongs to the Least Concern category. However, small populations with lower genetic diversity are particularly vulnerable. Various human impacts can further endanger these animals, such as poaching and hybridization with invasive species. Current research suggests that during the Younger Dryas period, red deer either became extinct in Ireland or survived only as a remnant population, traces of which remain in today's Killarney herd. For this reason, protecting the local herd is important, especially since its genetic integrity is constantly threatened by the presence of sika deer, which are capable of hybridizing with them.

Objectives: (i) to assess the applicability of tetramer microsatellite markers developed for red deer and the mitochondrial control region in sika deer; (ii) to estimate the genetic diversity of red deer and sika deer samples from Ireland; (iii) to examine the distinguishability of the two deer species based on their genotypes and haplotypes; (iv) to search for genetic patterns indicating hybridization based on the investigated markers.

In this study, we examined 11 red deer and 14 sika deer samples from Killarney National Park, as well as 16 red deer samples from Hungary, using ten microsatellite markers originally described for red deer and the mitochondrial control region. The amplified PCR products were analyzed using capillary electrophoresis and Sanger sequencing. We calculated haplotype diversity, actual and effective allele numbers, observed and expected heterozygosity, and the probability of identity (PI) values for both species.

All the markers used produced suitable PCR products in sika deer. The Hungarian red deer population exhibited the highest diversity in the analyzed values, followed by the Irish red deer and, lastly, the sika deer. Based on the allele set, the two species were clearly distinguishable at nine of the ten markers in the Irish samples, where we found no individuals exhibiting a mix of characteristic alleles from both species. In the mitochondrial control region, five haplotypes were detected in the Hungarian red deer, two in the Irish red deer, and one in the sika deer, which corresponded to the expected species in all cases.

Based on these results, all the red deer markers tested were found to be functional in sika deer. Across all examined indicators, the Irish red deer were more polymorphic than the sika deer but displayed lower genetic diversity compared to the Hungarian red deer. The two species were distinguishable based on the markers used in the Irish populations, and no signs of hybridization were found in the examined samples.