Question

Given the following cross TtYyRr x TtyyRr (T = tall; t = short Y = yellow; y = green R = round; r = wrinkled), what proportion of offspring would be expected to be short plants with round, green seeds. Write your answer as a reduced fraction - e.g. 1/2 proportion is

Answer 1

Answer:

3/32 ttyyR-  

Explanation:

Cross: Tall, Yellow, Rounded individuals with a tall, green, rounded individual

Parentals) TtYyRr      x      TtyyRr      

Gametes) TYR, TyR, TYr, Tyr, tYR, tyR, tYr, tyr (Parent one)

                 TyR, TyR, Tyr, Tyr, tyR, tyR, tyr, tyr (Parent two)

We need to know what proportion of offspring is expected to be short plants with round, green seeds. So we need to identify the gametes for these traits. The genotypes are:

• Shot → tt
• Round → RR or Rr
• Green → yy

⇒ Parent one can provide gametes tyR and tyr

⇒ Parent two can provide gametes tyR and tyr

(1/8 tyR x 2/8 tyR) + (1/8 tyR x 2/8 tyr) + (1/8 tyr x 2/8 tyR) =

2/64 ttyyRR + 2/64 ttyyRr + 2/64 ttyyRr =

1/32 ttyyRR + 2/32 ttyyRr =

3/32 ttyyR-