Objective To compare the sequence and expression level of tyrosinase gene (TYR) among four rabbit strains covering a wide range in the extent of iris pigmentation and to verify the relationship between the tyrosinase gene and the iris colour of rabbits. Methods Exons of TYR were amplified and directly sequenced. The relative expression level of TYR in different strains of rabbits was analyzed by real-time quantitative PCR. ResultsThe albino strains Japanese White and Rex rabbits showed a specific nucleotide exchange leading to an amino acid exchange (T373K) at the last N-glycosylation site. The silence nucleotide exchange (A→T) at nt870 of the tyrosinase coding sequence was observed in both the white hair black eyes (WHBE) and Chinchilla rabbits. A non-strain-specific amino acid exchange (V31M) was revealed in WHBE and Rex rabbits. The gene expression level of TYR in dark iris rabbits was significantly higher than that in non-pigmented ones. All results were corrected by the household gene GAPDH. ConclusionsThe nucleotide exchange at nt 1118 (C→A) affect the function of tyrosinase, and the findings indicate that the gene expression level of TYR is related with the phenotype of iris color in rabbits．