Preference for 1.6 mM saccharin by mice from inbred strains with different Tas1r3 genotypes at the T/C variant site at nucleotide position +179 (relative to the first nucleotide in the ATG start codon of the Tas1r3 gene). This polymorphism results in amino acid substitution of isoleucine to threonine at position 60 (I60T), in the extracellular N-terminus of the predicted T1R3 protein. Closed circles denote means for C57BL/6, C57L/J, CAST/Ei, CE/J, FVB/NJ, I/LnJ, IS/Cam, KK/HlJ, NOD/LtJ, NZB/BlNJ, P/J, RBF/DnJ, SEA/GnJ, SJL/J, SM/J, SPRET/Ei, ST/bJ and SWR/J strains with +179 T genotype. Mice from these strains strongly preferred saccharin (average preference score 88 ± 2%, Mean ± SE; n = 18). Open circles show means for 129P3/J, A/J, AKR/J, BALB/cByJ, BUB/BnJ, C3H/HeJ, CBA/J, DBA/2J, LP/J, PL/J, RF/J and RIIIS/J strains with +179 C genotype. Mice from these strains were indifferent to or only weakly preferred saccharin (average preference score 59 ± 3%, n = 12; p = 0.00000000012, t-test). Despite the strong phenotypical effect of the Tas1r3 genotype, there is also substantial variation in saccharin preference within each genotype group. As a result, Tas1r3 genotype explains only 78% of genetic variation in saccharin preferences among the inbred strains; the remaining 22% of genetic variance is attributed to the effect of other genes. Adapted with permission from .
Boughter and Bachmanov BMC Neuroscience 2007 8(Suppl 3):S3 doi:10.1186/1471-2202-8-S3-S3