Question

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.

Answer 1

Answer: e.Woman; there is not enough information to tell if the nondisjunction happened in meiosis I or II.

Explanation: There is not enough information to tell if the nondisjunction happened in meiosis I or II. Nondisjunction can occur during meiosis I and meiosis II, resulting in abnormal chromosomes number of gametes. The important difference between nondisjunction in meiosis 1 and Ii is that during meiosis 1, homologous chromosomes fail to separate while in meiosis II, sister chromatids fail to separate meaning it could have happened in meiosis I or II but we were not given.