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: Analyze the inheritance of seed shape

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

Step2: Analyze the inheritance of seed color

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

Step3: Use the multiplication rule

Since the inheritance of seed shape and seed color are independent events (Mendel's law of independent assortment), the probability of having green and wrinkled seeds ( \(rr\) and \(yy\)) is the product of the probabilities of each event.
\(P(rr\cap yy)=P(rr)\times P(yy)\)
Substitute \(P(rr)=\frac{1}{4}\) and \(P(yy)=\frac{1}{4}\) into the formula:
\(P(rr\cap yy)=\frac{1}{4}\times\frac{1}{4}=\frac{1}{16}\)

Answer:

1:16