A Microsatellite Genotyping-Based Genetic Study of Interspecific Hybridization between the Red and Sika Deer in the Western Czech Republic

Simple Summary The sika deer is a very flexible invasive species, capable of living dynamically in both large forests and mixed environment characterized by a prevalence of agricultural land. The Japanese sika deer was introduced to the Czech Republic at the end of the 19th century. The success of an introduced alien species may consist in their hybridizing with closely related taxa. Where few barriers to gene flow exist, rapid introgression of genetic traits from one species into another frequently occurs. The current Czech sika populations embody the most abundant and expanding group in continental Europe. In western Bohemia, we confirmed the interspecific hybridization with the native red deer. In this context, the red deer gene pool is endangered. The animals proliferate steadily in all directions and will most probably spread all over the Czech Republic if no major, timely changes in game management are adopted. Although inter-species hybrids between the red and sika deer can be phenotypically determined only exceptionally, there is the eventuality of identification via molecular genetic analysis. We used bi-parentally inherited microsatellite markers and a Bayesian statistical framework to re-examine the proportion of hybrids in the Czech red and sika deer populations. In total, 123 samples were collected, and the nuclear dataset consisted of 2668 allelic values. The number of alleles per locus ranged from 10 (BM1818) to 22 (BM888 and T193), yielding the mean of 16 alleles per locus across the deer. The mean allelic diversity of the red deer markedly exceeded that of the Japanese sika deer. Interspecific hybrids were detected, enabling us to confirm the genetic introgression of the sika deer into the red deer populations and vice versa in western Bohemia. The mean hybrid score equaled 10.6%, with 14.3% of the hybrids being among red deer-like individuals and 6.7% among sika-like ones. At two western Bohemian locations, namely, Doupovske hory and SlavkovskATIN SMALL LETTER Y WITH ACUTE les, the total percentages of hybrid animals equaled 18.8 and 8.9, respectively. No red deer alleles were detected in the sika populations of the subregions of Kladska, Zlutice, and Lany. The NeighborNet network clearly separated the seven red and sika deer sampling populations according to the geography. The knowledge gained from the evaluated data is applicable in hunting management to reduce hybridization with the European deer.