Reduction in frequency of the silver morph of the fox in eastern Canada resulting from the preferential harvest by hunters of the more valuable silver morph (69, 70). Reduction in frequency of the silver morph of the fox in eastern Canada resulting from the preferential harvest by hunters of the more valuable silver morph (69, 70). The points represent data presented by Elton (69). The lines represent the expected change in frequencies of the 3 phenotypes via selection at a single locus assuming that the silver fox morph has a 3% survival disadvantage per generation relative to the red and cross morphs. The initial frequency of the R allele was 0.3 and the mean generation interval was 2 years (70). Allendorf F W , Hard J J PNAS 2009;106:9987-9994 ©2009 by National Academy of Sciences