Suppose a mother carries two recessive genes for freckles (rr) and a father carries one recessive gene for freckles and one dominant gene for clear facial skin (Rr). What is the likelihood that their first child will have freckles?

Question

Responses
A

1 over 2
B

1 over 4
C

3 over 4
D
4 over 4

Answer 1

To determine the likelihood that the child will have freckles, we need to analyze the genetic combinations of the parents.

• The mother has two recessive genes for freckles (rr).
• The father has one recessive gene for freckles and one dominant gene for clear facial skin (Rr).

Now, we can set up a Punnett square to see the possible genetic combinations for the child:

      R  |  r
    __________
r |   Rr  |  rr
    __________
r |   Rr  |  rr

• The possible genotypes for the children are:
  • Rr (clear skin) - 2 occurrences
  • rr (freckles) - 2 occurrences

From the Punnett square, we can see that:

• There are 2 combinations that result in rr (freckles).
• There are 2 combinations that result in Rr (clear skin).

So, the likelihood of having a child with freckles (rr) is 2 out of 4, which simplifies to 1 out of 2.

Therefore, the answer is A. 1 over 2.