Figure 4.

Wild-type and peloric flowers of Antirrhinum majus. Darwin noted the near-complete dominance of the wild type and the segregation of the recessive allele in the F2. This is a floral trait determined by a single recessive allele and could have given Darwin the Mendelian ratios if he had pursued his breeding experiments. Photograph kindly provided by and copyright Enrico Coen. Reproduced with permission.