Question

An individual with genotype AaBbccDd is crossed to an individual with genotype aaBbCcDd. What is the probability that their first offspring will have genotype aabbCcDD?

a) 1/64

b) 1/32

c) 1/16

d) 1/8

e) 1/4

Answer 1

Answer:

a) 1/64

Explanation:

The cross is: AaBbccDd x  aaBbCcDd

If all genes are independent, we can analyze the cross of each gene to calculate the genotypic proportions in the offspring. Afterwords, we can use the Multiplication Rule of Probability to calculate the overall probability of having progeny of aabbCcDD genotype.

Aa x aa

1/2 Aa

1/2 aa

Bb x Bb

1/4 BB

2/4 Bb

1/4 bb

cc x Cc

1/2 Cc

1/2 cc

Dd x Dd

1/4 DD

2/4 Dd

1/4 dd

The rule of multiplication states that for independent events, the probability of all of them occurring at the same time can be calculated by multiplying the probability of each of them.

Then, the probability of having offspring with the aabbCcDD genotype will be: 1/2 × 1/4  × 1/2  × 1/4 = 1/64