Single-locus control of sucrose octaacetate tasting among mice.

SWRIJ mice avoid sucrose octaacetate (SOA) solutions at concentrations which other inbred strains do not. This phenotypic difference has been hypothesized to result from variation at a single autosomal locus with two alleles, one dominant (Soa a, aversion) and one recessive (Soa b, blind). Data from reciprocal F1 and F2 crosses of SWR/J (taster) and C57BL/6J (nontaster) mice and from four generations of selective lineal backcrossing to the C57BL/6J strain, in two-bottle preference tests with 10 -5 M SOA, were used to test this monogenic model against two polygenic models. The phenotypic ratios expected in the segregating generations according to the single-locus model were consistent with the observed ratios. The ratios expected with either two-locus model were inconsistent with those found. A strain distribution pattern, also consistent with monogenic variation, was found when a set o f recombinant inbred strains (SWXL/Ty) derived from SWR/J and C57L/J (nontaster) mice was similarly tested. Outbred CFW mice (inbred substrains of which had been reported by separate laboratories to be both SOA tasters and SOA nontasters) were found to be polymorphic for SOA tasting, An allele identical by descent to that in the SWR/J strain may be segregating in this (distantly) related line.