Q46 - Tracing a De Novo Haemophilia Mutation Through European Royalty
Robert Macfarlane (1907-1987) explained the biochemistry of blood clotting, and discovered the cause of haemophilia B, which causes fatal bleeding. Queen Victoria’s son, Prince Leopold, was the first European noble to develop haemophilia B, but it quickly devastated European royal lines. An incomplete family tree is shown.
This question mixes multiple-choice/numeric-estimate parts with True/False statements - answer each part using the information and data above.
A. Given the pedigree, what is the probability that Alexis (a great-grandson of Queen Victoria through an unaffected daughter) inherited the haemophilia B mutation?
B. In this family, haemophilia B could have originated from a new (de novo) mutation during meiosis in Queen Victoria's oocytes.
C. Clotting factor activity is reduced by more than half in these haemophiliacs.
Question reproduced from IBO 2017, Theoretical Exam B, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Official answer key & worked solutions