38. Hemophilia is an X-linked recessive trait. In a family, the mother knows she

Question

38. Hemophilia is an X-linked recessive trait. In a family, the mother knows she is a carrier and the father does not have the disease. The family is expecting triplets. They are worried about having boys that would have 50% chance of being affected. What is the probability of having one or more than one boy? Consider two scenarios: if the triplets are monozygotic and if the triples are trizygotic. A) 1/2 and 7/8 B) 1/2 and 1/8 C) 2/3 and 1 D) 1/3 and 1/3 E) none of the above answers is correct 39. Consider the following human pedigrees of a rare autosomal recessive disease. Assume all people marrying into the pedigree do not carry the abnormal allele. What

Explanation / Answer

Q.38 Answer- (A)

In monozygotic condition all the three children could be either boys or girls i,e we would have only two cases either all three are boys or all three are girls.

Therefore the probability in this condition is 1/2.

In trizygotic condition the sample space(probability) is as under (G for girl and B for boy) :-

GGG, BBG, GBG, BGB, GGB, BBG, BGG, GBB

From the above given sample space , it is clear that among eight possible conditions , seven of them have either one or more boy in them. Therefore the answer is 7/8.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.