Hemophilia was called the royal disease because many of the European royal famil

Question

Hemophilia was called the royal disease because many of the European royal families had members afflicted with hemophilia. Hemophilia is a sex-linked, recessive, X-chromosome disorder, It was known that Queen Victoria was unaffected but was a carrier of the hemophilia gene (XHXt1), Suppose Queen Victoria's husband, Prince Albert, was affected with hemophilia (X?Y). What is the percent probability that a son of Queen Victoria and Prince Albert would be unaffected? What is the percent probability that Queen Victoria and Prince Albert will have an affected child either male or female)? What is the percent probability that Queen Vctoria and Prince Albert will have two affected females?

Explanation / Answer

In humans the probability of a couple having a male or a female child is 50% that is 1/2. There is a chance of having either a male or a female with equal probability. In the case of recessive X linked disorder when the mother is a carrier and father is affected, then the chance of the female getting affected is 50% and the chance of a male getting affected is 50% as one X chromosome is received from mother and one from father. If the male receives the unaffected allele from the mother then he is not affected and if he receives the recessive allele from the mother then he would be affected as the male has the chance of receiving X chromosome only from his mother.

So, in this case a cross between a heterozygous carrier female and an affected male

              XHXh × XhY gives two females and two males with the following genotypes:

             XhY – Affected male

              XHY – Unaffected male

              XHXh – Carrier female

              XhXh – Affected female

From the above cross the probability of having a male is 1/2 and among them the probability of having an unaffected male is 1/2 which is equal to 50%.

The percent probability that a son of Queen Victoria and Prince Albert would be unaffected is 50%.

Considering the cross made the number of affected children out of the offsprings is 50% when both males and females are considered.

Therefore, the percent probability that Queen Victoria and Prince Albert will have an affected child either male or female) is 50%.

The percent probability that Queen Victoria and Prince Albert will have two affected females is 6.25%.

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

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