Sex-Linked Inheritance Problem Set

Problem 9: Tracing the inheritance of the human X chromosome

Tutorial to help answer the question

Women have sex chromosomes of XX, and men have sex chromosomes of XY.
Which of a women's grandparents could not be the source of any of the genes on either of her X-chromosomes?

Tutorial

X chromosome inheritance

The X chromosomes are inherited from either maternal grandparent and paternal grandmother
The diagram shows how the X and Y chromosomes are inherited from the maternal and paternal grandparents to the parents to the son.
The Y chromosome is passed strictly from the father to male children in each generation.
No male from the father's side of the family can be a source of genes on a women's X chromosome.

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University of Arizona
Updates: July 15, 1999
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