Hemophilia A is an X-linked blood clotting disorder. A normal man and a woman with hemophilia A have a child with Turner Syndrome. This child does not have hemophilia. In whom did non-disjunction occur? In meiosis I or meiosis II?
A) Woman; meiosis I
B) Woman; meiosis II
C) Man; meiosis I
D) Man; meiosis II
E) Woman; there is not enough information to tell if the nondisjunction happened in meiosis I or II.

Question

Quizplus · Accepted Answer

Turner Syndrome is characterized by a female having only one X chromosome (45,X instead of the normal 46,XX or 46,XY). Since the child inherited hemophilia A from the mother and has Turner Syndrome, it indicates a loss of one sex chromosome. However, without specific information on the chromosomal composition of the gametes involved, it's impossible to determine at which stage of meiosis (I or II) the nondisjunction occurred in the woman.

Hemophilia a Is an X-Linked Blood Clotting Disorder