Question

In considering the cross YyRr x YyRr, the phenotype ratios of the F2 generation will be _____.

Answer 1

Well F1 will have the typical 9:3:3:1 GENOTYPE

Answer 2

One relevant piece of info is whether its dominant or recessive

Answer 3

Now F2 will just be a cross between the F1 progeny

Answer 4

Sorry I made a mistake its a 9:3:3:1 phenotype if both traits are dominant (which is usually the case in such problems)

Answer 5

All possible GENOTYPES for F1= YYRR:YYRr:YYrr : YyRR:YyRr:Yyrr : yyRR:yyRr:rr = 1:2:1 : 2:4:2 : 1:2:1 = 16 possible combinations (do you see the pattern?

Answer 6

completing the F2 punnet square is not a trivial thing, because the PROBABILITY of gametes is not equal. This seems to much work and too complicated. Are you sure they do not ask for F1? They may ask to make a specific cross between F1 and some other genotype

Answer 7

Is d given cross f1 progeny selfed?

Answer 8

If that is true, then you need some linear algebra!

Answer 9

F1 has 9 possible genotypes in ratios of 1:2:1:2:4:2:1:2:1 so the YyRr (4) x YyRr (4) cross is 16 times more likely then, say, a YYRR (1) x YYRR (1) cross

Answer 10

at this point you need a 9 x 9 matrix (81) and each element will represent one UNIQUE cross

Answer 11

Yeah this is just a bunch of busy work!