Identification of an olfactory imprinting-related gene in the lacustrine sockeye salmon, Oncorhynchus nerka

The olfactory system of salmonids is essential for imprinting and the subsequent homing migration. Olfactory imprinting-related genes were identified in the olfactory system of 1- and 3-year-old lacustrine sockeye salmon (Oncorhynchus nerka) using a subtractive hybridization technique of representational difference analysis (cDNA-RDA). We have obtained a partial clone from a subtractive cDNA library of 1-year-old fish that contains a 756 bp open reading frame coding for a putative protein with 252 amino acid residues named the Sockeye salmon Olfactory system Imprinting related Gene (SOIG). By northern hybridization, the SOIG mRNA was only expressed in the olfactory epithelium and not in other tissues. In situ hybridization showed that the expression of SOIG mRNA was observed in the olfactory receptor cells and basal cells of the olfactory epithelium. This suggests that SOIG could have specific and important roles in olfactory system.