Question

in a dihybrid cross for round and yellow seeds (rryy x rryy), what is the probability of having green and wrinkled seeds? key: r = round r = wrinkled y = yellow y = green 1:16 3:16 8:16 9:16

Explanation:

Step1: Determine the probability of wrinkled seeds

For the seed shape trait (\(Rr\times Rr\)):
The Punnett - square for \(Rr\times Rr\) gives genotypes \(RR:Rr:rr = 1:2:1\). The probability of getting \(rr\) (wrinkled) is \(P(rr)=\frac{1}{4}\).

Step2: Determine the probability of green seeds

For the seed color trait (\(Yy\times Yy\)):
The Punnett - square for \(Yy\times Yy\) gives genotypes \(YY:Yy:yy = 1:2:1\). The probability of getting \(yy\) (green) is \(P(yy)=\frac{1}{4}\).

Step3: Use the multiplication rule for independent events

Since seed shape and seed color are independent traits (Mendel's law of independent assortment), the probability of getting wrinkled and green seeds (\(rryy\)) is \(P(rryy)=P(rr)\times P(yy)\).
Substitute \(P(rr)=\frac{1}{4}\) and \(P(yy)=\frac{1}{4}\) into the formula: \(P(rryy)=\frac{1}{4}\times\frac{1}{4}=\frac{1}{16}\).

Answer:

A. \(1:16\)