Question

Albinism, lack of pigmentation in humans, is an autosomal recessive disorder. A normally pigmented woman who has an albino uncle wishes to marry a phenotypically normal man whose sister is an albino. (Assume that these are the only individuals known to be albino in the two families) What is the probability that the couple's first child is an albino girl

Answer 1

The probability that the couple in question will have an albino girl is 12.5%, calculated as 25% chance of having a child with albinism and a 50% chance of having a girl, multiplied together.

Step-by-step explanation:

The student has asked about the probability that a couple will have an albino girl considering their familial history of albinism. Albinism is an autosomal recessive disorder, which means that it is a hereditary disease carried on non-sex chromosomes and two copies of the gene are necessary for the phenotype to be expressed. Since albinism does not have any effect on gender, we can calculate the probability of having an albino child separately from the probability of having a girl.

To determine the probability of having an albino child, we must consider the genetic background of the parents. Given that the woman has an albino uncle, and assuming her parents are not albino, it can be inferred that her genotype is Aa, where 'A' is the allele for normal pigmentation and 'a' is the allele for albinism. Her fiancé, whose sister is albino, must also have parents who are not albino, making his genotype Aa as well.

Using a Punnett square, the genetic outcomes for their children can be AA, Aa, Aa, and aa. The only genotype that results in albinism is aa, which has a probability of 1 out of 4, or 25%. To have a girl, there's a separate 50% chance (since sex determination is independent of albinism). Therefore, the overall probability of having an albino girl is the product of both probabilities: 25% (chance of albinism) × 50% (chance of being a girl) = 12.5%.

Answer 2

Hi, you've asked an incomplete question. The missing options read;

a. 1/6

b. 1/9

c. 1/18

d. 1/36

e. none of these choices

Answer:

e. none of these choices

Step-by-step explanation:

Remember, someone with an h.o.m.o.z.y.g.o.u.s gene basically inherits two identical alleles; one from their biological mother and the other their biological father.

In this scenario, the real concern should be to determine the probability that the girl child inherits a dominant allele that contains the gene that causes albinism. Hence, since there's little information about the gene type of the parents, a concise assumption can be made, thus rendering the listed options unlikely.