Evolution, Vol. 50, No. 1 (Feb., 1996), pp. 163-173 (11 pages) Phenotypic evolution in contemporary populations can generally be witnessed only when novel selective forces produce rapid evolution.

Figure 1: Candidate genes in the region of the Sac locus. Human and mouse T1R3 are members of the family 3 subtype of GPCRs, all of which contain large extracellular domains. Other family 3 subtype ...