Now that you understand inheritance of skin color in tree frogs, you want to study eye color inheritance. You cross a true breeding brown-eyed tree frog to a true breeding red-eyed tree frog and obtain heterozygous F1 progeny. The F1 are crossed to create the F2 progeny. How can you determine if one or two genes are involved in inheritance of eye color? Since we are looking at only one trait (eye color) only one gene must be involved. Look at the ratios of the F2 progeny, if it is represented in 16ths, then one gene is involved. Look at the ratios of the F2 progeny, if it is represented in 4ths, then one gene is involved. Look at the phenotypes of the F2 progeny, if only two eye colors are observed in the progeny then one gene is involved.