Question

Consider the cross $AaBbCcDdEe\times aaBbccddee$. What proportion of the progeny will genotypically resemble the first parent?

• A. $1/64$
• B. $2/64$
• C. $4/16$
• D. $4/46$

Answer 1

Answer: (A)

In such genetic cross, each gene is crossed separately and then probability of desired progeny is obtained by multiplying the probability of each gene as shown below:

Aa x aa Bb x Bb Cc x cc Dd x dd Ee x ee

↓ ↓ ↓ ↓ ↓

Aa Aa aa aa BB Bb bB bb Cc Cc cc cc Dd Dd dd dd Ee Ee ee ee

​Probability of :

Aa is 2/4, Bb is 1/4, Cc is 2/4, Dd is 2/4, Ee is 2/4

So, combined probability is 2/4x1/4x2/4x2/4x2/4=1/64

Therefore, A) 1/64 is correct.