Two parents have a daughter with one X chromosome Genetic st

Two parents have a daughter with one X chromosome. Genetic studies indicate the X chromosome came from the mother. When did the nondisjunction event occur? In the father during meiosis II In the father but the stage of meiosis cannot be determined In the mother during meiosis II In the mother but the stage of meiosis cannot be determined You cannot determine the parent or the stage of meiosis

Solution

Answer is option B In the father but the stage of meiosis cannot be determined.

Nondysjunction is condition where the sister chromatids fail to separate. In meiosis, the chromosomes are halved and distributed to the resulting 4 cells equally. When Nondysjunction occurs, some gametes receive extra chromosomes and some receive a chromosome less than normal. This Nondysjunction can occur both at meiosis l and ll.