Treehoppers have either purple, or green, or white skin.
Other geneticists have determined that:
(1) whenever one white treehopper is mated with another white treehopper all the progeny are white.
(2) whenever two pure bred purple treehoppers are mated all their progeny are purple.
(3) whenever two pure bred green treehoppers are mated all their progeny are green.
(4) whenever a pure bred green treehopper is mated with a pure bred purple treehopper all their
progeny are purple.
The information provided above is not sufficient to allow you to explain completely the inheritance of skin color in the treehopper. Therefore you mate a pure bred purple treehopper with a pure bred white treehopper. All the F1 progeny are purple. You then inbreed the individuals in the F1 generation to obtain an F2 generation. The F2 progeny appear with the following phenotypes:

P: purple X white
F1: purple
F2: 9000 purple 3000 green 4000 white out of 16000 total.

a. Based on this data, how many genetic loci control skin color in the treehopper and why is there this amount of genetic loci?
b. Define symbols and assign genotypes to the original purple and white parents in this cross.
Symbols =

Purple parent:
White parent: