Consider two coat-color loci (R/r, G/g), where the genotypes have the following phenotypes R-G- = yellow, rrG- = green, R-gg = red, rrgg = white. Two yellow parents (which we denote P1 and P2) are choosen and crossed to several different parents, and the following data are observed:

• When crossed to a purebreeding green parent, both yellow parents gave equal number of yellow and green offspring.

• When crossed to a purebreeding red parent, both yellow parents gave equal numbers of red and yellow offspring.

• When crossed to a white parent, the first (P1) yellow parent gave equal numbers of yellow and white offspring.

• When crossed to a white parent, the second (P2) yellow parent gave equal numbers of red and green offspring.

Provide a complete genetic model accounting for these data.