The class I olfactory receptor olfactory sensory neuron (OSN) enhancer was targeted with sgRNAs (targeting CACCGTCTCATTGCCACCCGGATGA, AAACTCATCCGGGTGGCAATGAGAC, CACCGCCCCTCCACCGTACTTGCA and AAACTGCAAGTACGGTGGAGGGGC) using CRISPR/Cas9 technology, resulting in a 1982 bp deletion. (J:254398)