A lethal disease of the European bison - posthitis is conditionally determined by its genomics.

Posthitis is an incurable lethal disease of males in the European bison ( Bison bonasus ), regarded as one of the major threats of the survival of the iconic species. Multiple attempts have been undertaken in the last 30 years to identify a source of infection and a primary pathogen. A genetic background for the disease was suggested after tools developed for cattle ( Bos taurus ) permitted the discovery of genomic regions possibly associated with the occurrence of posthitis . In this study, we applied deep coverage targeted sequencing to 74 regions on 10 of the bison’s chromosomes (1, 9, 12, 13, 15, 23, 25, 26, 29, and X) in a search for species-specific single nucleotide polymorphism (SNP) markers that could help to explain the mechanism of the disease and be used to test for posthitis susceptibility. The association results were ranked based on p-values lower than 0.005 and odds ratios (OR) higher than 1. We obtained 30 SNP markers within these requirements, all located on chromosome 25. Major difficulties are conditional nature of posthitis and ‘false negative’ sampling. Thus we recommend complex genomic and environmental factors association assay that could eventually explain the puzzling etiology of the disease and support the species conservation.