The sequence of the tyrosinase (Tyr) gene coding tracts has been obtained for 
the gorilla (Gorilla gorilla gorilla). The five exons of the gene were sequenced 
in three gorillas and in a normally pigmented human. The tyrosinase gene has 
been found to be a very conserved locus with a very low substitution rate. Some 
nucleotide and amino acid differences were found between the gorilla and human 
tyrosinase coding sequences. One of the gorillas included in the study is the 
only known case of albinism in a gorilla ('Snowflake'). Mutations of the TYR 
gene lead to Oculocutaneous Albinism type 1 (OCA1), the most common type of 
albinism in humans (OMIM accession number 203100). The TYR gene encodes the 
tyrosinase enzyme (E.C. 1.14.18.1), whose activity was found to be completely 
lacking in 'Snowflake', indicating that a mutation in the Tyr gene is the likely 
cause of his albinism. Nonetheless, no nucleotide changes were detected that 
could account for the lack of Tyr product or tyrosinase activity in Snowflake, 
and explanations of these findings are discussed.