Question

each of two parents has the genotype brown/blond, which consists of the pair of alleles that determine hair color, and each parent contributes one of these alleles to a child. assume that if the child has at least one brown allele, that color will dominate and the childs hair color will be brown.
a. list the different possible outcomes. assume that these outcomes are equally likely.
b. what is the probability that a child of these parents will have the blond/blond genotype?
c. what is the probability that the child will have brown hair color?

a. list the possible outcomes
a. brown/blond and blond/brown
b. brown/brown and blond/blond
c. brown/brown, brown/blond, and blond/blond
d. brown/brown, brown/blond, blond/brown, and blond/blond

Explanation:

Part a:

Step1: Analyze Parent Genotypes

Each parent has genotype brown/blond, so each can contribute either brown (B) or blond (b) allele.

Step2: List Possible Combinations

• First parent contributes brown, second contributes brown: brown/brown
• First parent contributes brown, second contributes blond: brown/blond
• First parent contributes blond, second contributes brown: blond/brown
• First parent contributes blond, second contributes blond: blond/blond

So the possible outcomes are brown/brown, brown/blond, blond/brown, and blond/blond.

Step1: Total Possible Outcomes

From part a, there are 4 possible outcomes (brown/brown, brown/blond, blond/brown, blond/blond).

Step2: Favorable Outcomes for blond/blond

There is 1 favorable outcome (blond/blond).

Step3: Calculate Probability

Probability = $\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$ = $\frac{1}{4}$

Step1: Total Possible Outcomes

Again, total outcomes are 4 (from part a).

Step2: Favorable Outcomes for brown hair

Brown hair occurs when at least one brown allele is present. The favorable outcomes are brown/brown, brown/blond, blond/brown. So there are 3 favorable outcomes.

Step3: Calculate Probability

Probability = $\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$ = $\frac{3}{4}$

Answer:

D. brown/brown, brown/blond, blond/brown, and blond/blond

Part b: