Genomic variability in the extinct steppe bison (Bison priscus) compared to the European bison (Bison bonasus)

In 2009, a frozen mummy of the steppe bison (SB) (Bison priscus) was discovered between the lower Kolyma River and the Alazeya River in northeast Siberia, Russia. The specimen was dated with ¹⁴C and estimated to have lived more than 48,000 ¹⁴C years before present (BP). The relationship between SB and the European Bison (EB) (Bison bonasus), also known as wisent or European wood bison, is unresolved and it is unclear whether the SB and EB overlapped in space and time. The aim of our study was to compare genetic variability between the SB specimen and modern EB. We expected higher SB variability due to substantial bottlenecks in the EB approximately one century ago when it became extinct in the wild. The EB (n = 167) and the SB specimen were genotyped with the Illumina BovineHD BeadChip with 777,962 single-nucleotide polymorphism (SNP) markers. Steppe bison DNA was extracted and genotyped six times to account for genotyping errors due to low-quality DNA. We obtained a final set of 7786 SNPs. The mean number of private alleles in EB was 0.027 (± 0.0002) and in SB, it was 0.288 (± 0.0006). This could be explained by factors including differences between species, spatiotemporal divergence, and bottleneck effects. Investigation of historic EB samples could help resolve phylogenetic relationships, the role of the recent bottleneck, and provide information for conservation management to reduce the incidence of disease in the population and maintain its evolutionary potential.