Baldness is a dominant trait that is influenced by an individual's sex. A man will become bald if he has the genotype BB or Bb. A man who is bb will not become bald. A woman will have thinning hair, but not become totally bald, if she is BB. A woman will not become bald, or have thinning hair, if she is Bb or bb. What will be the outcome if a woman who is XXbb produces a child with a man who is XYBb? a There is a 75% chance that the child will not become bald. b There is a 25% chance that the child will not become bald. c There is a 100% chance that the child will become bald. d There is a 50% chance that the child will become bald.

Answer 1

To solve this problem, we need to examine the genotypes of the parents and determine the potential genotypes of their offspring.

Parental genotypes:

• Woman: XXbb (she is a female and has two X chromosomes, and is homozygous recessive for the baldness gene (bb))
• Man: XYBb (he is a male with one X chromosome and one Y chromosome, and is heterozygous for the baldness gene)

Possible gametes:

• The woman can only produce Xb gametes (since she is bb).
• The man can produce two types of gametes: XB (with the dominant baldness allele) and Y (which carries no baldness allele).

Possible offspring genotypes: When we combine the gametes from both parents, the possible combinations are:

1. Xb from the mother and XB from the father: XBXb (bald)
2. Xb from the mother and Y from the father: XYb (not bald)

Now, let's determine the phenotypes based on the offspring combinations:

1. XBXb (bald) - This child will become bald because they inherit at least one dominant allele (B) from the father.
2. XYb (not bald) - This child will not become bald because they have the genotype bb (with respect to baldness).

Now let's count the outcomes:

• 1 child with genotype XBXb (bald)
• 1 child with genotype XYb (not bald)

Total outcomes:

• Probability of child becoming bald = 1 out of 2 = 50%
• Probability of child not becoming bald = 1 out of 2 = 50%

Based on this analysis, the answer to the question is: d. There is a 50% chance that the child will become bald.