A feral donkey population (Equus asinus), living in the Asinara National Park 
(an island north-west of Sardinia, Italy), includes a unique white albino donkey 
subpopulation or colour morph that is a major attraction of this park. 
Disrupting mutations in the tyrosinase (TYR) gene are known to cause recessive 
albinisms in humans (oculocutaneous albinism Type 1; OCA1) and other species. In 
this study, we analysed the donkey TYR gene as a strong candidate to identify 
the causative mutation of the albinism of these donkeys. The TYR gene was 
sequenced from 13 donkeys (seven Asinara white albino and six coloured animals). 
Seven single nucleotide polymorphisms were identified. A missense mutation 
(c.604C>G; p.His202Asp) in a highly conserved amino acid position (even across 
kingdoms), which disrupts the first copper-binding site (CuA) of functional 
protein, was identified in the homozygous condition (G/G or D/D) in all Asinara 
white albino donkeys and in the albino son of a trio (the grey parents had 
genotype C/G or H/D), supporting the recessive mode of inheritance of this 
mutation. Genotyping 82 donkeys confirmed that Asinara albino donkeys had 
genotype G/G whereas all other coloured donkeys had genotype C/C or C/G. 
Across-population association between the c.604C>G genotypes and the albino coat 
colour was highly significant (P = 6.17E-18). The identification of the 
causative mutation of the albinism in the Asinara white donkeys might open new 
perspectives to study the dynamics of this putative deleterious allele in a 
feral population and to manage this interesting animal genetic resource.