are crossbred, the result? When members of two different true-breeding strains of straight-haired guinea pigs are crossbred, the result is always is always curly-haired. Two of these curly-haired F1s are mated several times, and when the phenotypes of their offspring are tallied, there are 59 curly and 41 straight-haired guinea pigs. When either two straight-haired F2s or two curly F2s are mated, the offspring are a mix of straight- and curly-haired pups. This trait involves two genes.
I have no idea how to make a cross like this that allows all F2 combinations of the same phenotype to produce multiple phenotypic responses
I have no idea how to make a cross like this that allows all F2 combinations of the same phenotype to produce multiple phenotypic responses