Question

in pepper plants, green fruit color (g) is dominant to red fruit color (g) and round shaped fruit (r) is dominant to square shaped fruit (r). these two genes are located on different chromosomes. cross parent 1 that is homozygous recessive for fruit color and heterozygous for fruit shape with parent 2 that is heterozygous for fruit color and homozygous dominant for fruit shape. hint: you must use foil (first, outer, inner, last) to determine the gametes of the parents (what goes on the outside of the squares). may want to do this on scratch paper!!! f o i l parent 1 genotype = ggrr foil to make gametes: __ parent 2 genotype = ggrr foil to make gametes: make sure to put alleles in order of foil. parent 1 on the top. parent 2 on the side. <<parent 1 ^^ parent 2 phenotype probabilities: green and round = (fraction) green and square = (fraction) red and round = (fraction) red and square = __ (fraction) = gr = gr = gr = ggrr = ggrr = ggrr = ggrr = 3/16 = 4/16 = 8/16

Explanation:

Step1: Identify Parent 1 gametes (FOIL)

Parent 1 genotype: $ggRr$.
First: $gR$, Outer: $gr$, Inner: $gR$, Last: $gr$
Gametes: $gR, gr, gR, gr$

Step2: Identify Parent 2 gametes (FOIL)

Parent 2 genotype: $GgRR$.
First: $GR$, Outer: $Gr$, Inner: $gR$, Last: $gr$
Gametes: $GR, Gr, gR, gr$

Step3: Fill Punnett Square

Combine gametes row (Parent1) × column (Parent2):

1. $gR × GR = GgRR$
2. $gR × Gr = GgRr$
3. $gR × gR = ggRR$
4. $gR × gr = ggRr$
5. $gr × GR = GgRr$
6. $gr × Gr = Ggrr$
7. $gr × gR = ggRr$
8. $gr × gr = ggrr$
9. $gR × GR = GgRR$
10. $gR × Gr = GgRr$
11. $gR × gR = ggRR$
12. $gR × gr = ggRr$
13. $gr × GR = GgRr$
14. $gr × Gr = Ggrr$
15. $gr × gR = ggRr$
16. $gr × gr = ggrr$

Step4: Count phenotypes

• Green (G_) and Round (R_): $GgRR, GgRr, GgRr, GgRR, GgRr, GgRr$ → 8 total
• Green (G_) and Square (rr): $Ggrr, Ggrr$ → 2 total
• Red (gg) and Round (R_): $ggRR, ggRr, ggRr, ggRR, ggRr, ggRr$ → 6 total
• Red (gg) and Square (rr): $ggrr, ggrr$ → 2 total

Total offspring: 16

Step5: Calculate probabilities

Green and Round: $\frac{8}{16} = \frac{1}{2}$
Green and Square: $\frac{2}{16} = \frac{1}{8}$
Red and Round: $\frac{6}{16} = \frac{3}{8}$
Red and Square: $\frac{2}{16} = \frac{1}{8}$

Answer:

Parent 1 Gametes: $gR, gr, gR, gr$
Parent 2 Gametes: $GR, Gr, gR, gr$
Punnett Square (top to bottom, left to right):
$GgRR, GgRr, ggRR, ggRr$
$GgRr, Ggrr, ggRr, ggrr$
$GgRR, GgRr, ggRR, ggRr$
$GgRr, Ggrr, ggRr, ggrr$

Phenotype probabilities:
Green and Round = $\frac{1}{2}$
Green and Square = $\frac{1}{8}$
Red and Round = $\frac{3}{8}$
Red and Square = $\frac{1}{8}$