One of the genetic loci influencing alcohol preference in mice, Ap3q (alcohol preference 3 QTL), maps to a region of chromosome 4 overlapping with the Tas1r3 gene.[190] This suggests that the Tas1r3 gene is identical to the Ap3q locus. Consistent with this, allelic variation of the Tas1r3 gene in congenic and knockout mice has pleiotropic effects on ingestive responses to sweeteners and ethanol in the long-term and brief-access tests, and influences taste quality perception of ethanol.[191-193] These data suggest that Tas1r3 alleles influence perception of the sweet taste component of ethanol flavour. As a result, mice with a more sensitive variant of the sweet taste receptor perceive stronger sweetness from ethanol, which makes it more hedonically attractive and promotes ethanol intake.
