In the summer squash, fruits may be white, yellow, or green. In one case, the cross of yellow X white produced an F1 of all white-fruited plants that, when selfed, gave an F2 segregating 12 white: 3 yellow: 1 green. (a) suggest gnotypes for the white, yellow, and green phenotypes. (b) give genotypes of the P, F1, and F2 of this cross.

Question

In the summer squash, fruits may be white, yellow, or green. In one case, the cross of yellow X white produced an F1 of all white-fruited plants that, when selfed, gave an F2 segregating 12 white: 3 yellow: 1 green. (a) suggest gnotypes for the white, yellow, and green phenotypes. (b) give genotypes of the P, F1, and F2 of this cross. 
Biology genetics - bobpursley Friday, January 5, 2018 at 11:04pm 
P: Yg x WW yellow x white 
F1: YW,YW, gW, gW all white 
F2: 
first two YY,YW,WW,YW one Yel, 3W 
first, third Yg,YW,Wg,WW one Yel, 3W 
first, fourth Yg,YW,Wg,WW one Yel, 3W 
second third Yg,YW,Wg,WW one Yel, 3 W 
third, fourth gg,gW, Wg, WW one g, 3W 
now if W dominates to y,g, and Y dominates to g, then I count 15/20 W, 1/20 g, and 3/20 yellow 
Now in the F2 above, there were 12/16 W,3/16 Yellow, and 1/16 green Those frequencies look very close to what I laid out. 
White 12 
Yellow 4 
green

I have tried many ways and cannot figure out the answers provided. Could you please show me how you came up with these answers?

Writeacher · Answer

Jiskha doesn't have a biology expert at present, but you might be able to find information here:
https://www.khanacademy.org/science/biology

Scroll down to the sections that include "genetics" in their titles and you might find the information you need.