Known loci in the KIT and TYR genes do not explain the depigmented white coat colour of Austro-Hungarian Baroque donkey

The Italian Asinara donkey and the White Austro-Hungarian Baroque donkey share an identical coat colour phenotype which is characterised by unpigmented skin, white hair, white hooves and blue eyes. Whereas for the Asinara donkey the white coat colour phenotype was assigned to a recessive inherited missense mutation in the Tyrosinase gene (TYR), the underlying genetic background in the White Austro-Hungarian Baroque donkey has not been studied yet. Historical documents derived by the presence of Austro-Hungarian prisoners in the Asinara Island during the First World War might suggest a possible common origin of the same coat colour phenotype in the two breeds. Genotyping of this mutation in the TYR gene and the loci in the KIT gene associated with Dominant White and White Spotting phenotype, revealed, that none of the mutated alleles segregated in the White Austro-Hungarian Baroque Donkey breed. Also sequencing analysis of the TYR gene did not result in the detection of further candidate variants. Therefore, the TYR gene can be excluded as a possible candidate gene for this specific coat colour in the White Austro-Hungarian Baroque donkey. This result excludes a common genetic origin of the white coat colour of the Asinara and White Austro-Hungarian Baroque donkeys that historical documents could have suggested.Highlights Historical information indicated that the white (albino) Asinara donkey breed and the White Austro-Hungarian Baroque donkey breed could be genetically related. The TYR mutation identified in Asinara donkeys and known polymorphic sites in the KIT gene associated with depigmented white coat colour in donkeys do not segregate in the White Austro-Hungarian Baroque Donkey. Due to different underlying genetic background of one identical phenotype in two populations, no common ancestors can be assumed between Asinara donkey and White Austro-Hungarian Baroque donkey throughout the last century.