A SLC45A2 mutation is strongly associated with the cream dilution in Baroque donkeys

Domestic Baroque donkeys are popular animals in many European parks and zoos. Although their cream coat color is very charismatic, the underlying genetics is still undiscovered. Addressing this question, a candidate approach was used to search for the causative mutation.Considering the knowledge from domestic horses, the Solute Carrier Family 45 Member 2 (SLC45A2) was identified as the most promising candidate. Samples from 77 domesticated donkeys, 11 wild equids, 1 mule and 2 domestic horses were included in comparison. All exons and the flanking intron sequences of the SLC45A2 were sequenced (2774bp).Sequence comparison revealed that a mutation found exclusively in exon 7 transmembrane region 11 (c.1457C>T; p.Ala486Val) is very likely responsible for the charismatic coat color phenotype in Baroque donkeys. Family studies produced evidence for an autosomal recessive mode of inheritance. Since the coat color in Baroque donkeys varies from almost white to gold, the question remains whether the base coloration, which in mammals is regulated by the ASIP and MC1R genes, also have an impact but no remarkable mutations were found in Baroque donkeys.