A construct comprised of a stretch of 9 equally spaced repeats of the homeodomain binding sequence upstream of a minigene with 405 base pairs upstream of the transcription start site of Olfr16, an intact Olfr16 coding sequence, and an IRES-tauGFP cassette just after the stop codon along with a second construct identical except for the substitute of IRES-taumRFP were coinjected into (C57BL/6J x CBA)F2 pronuclei. (J:166885)