A refined genome-wide association study of posthitis in lowland Białowieza population of the European bison (Bison bonasus)

Necrotic inflammation of the prepuce (NIP, posthitis) is probably the most serious threat to the males of European bison (Bison bonasus) population living in the Białowieża National Park. Approximately 6% of the males have been affected every year. The aim of this study was to explore genetic regions potentially affecting this disease. The population was divided into two groups: healthy (25) and affected by posthitis (112). All individuals were genotyped with the Illumina BovineHD BeadChip. Tests performed on a single-locus mixed model (EMMAX) resulted in one SNP on the 25th chromosome (rs134172402) showing statistically important association with the posthitis incidence. The closest candidate gene located near this SNP was the periplakin (PPL) coding protein associated with skin development and some autoimmunity skin diseases such as pemphigus foliaceus or atopic dermatitis. Therefore, we conclude that PPL might be the candidate gene for posthitis, but further studies are necessary to confirm its expression and role in affected tissues.