Eighteen bp changes resulting in 6 amino acid substitutions (A146V, V151M, A157T, G161S, V194I, D205N) and an IRES-taulacZ gene were introduced via homologous recombination. The resulting protein is a hybrid between Olfr151 and Olfr160 which have a total of 25 bp and 11 amino acid differences. The lacZ gene was fused after the stop codon and co-expressed with the mutant protein.