During the formation of female gametes, nondisjunction of X chromosomes may occur during meiosis I, resulting in two types of eggs with different compositions of sex chromosomes. If normal sperm fertilize these two types of egg, which of the following are possible sex chromosome complements in the resulting fertilized egg?

Question

Quizplus · Accepted Answer

When nondisjunction of X chromosomes occurs during meiosis I in females, two types of eggs are produced: one with two X chromosomes and the other with no X chromosome. If these two types of eggs are fertilized by normal sperm, the possible sex chromosome complements in the resulting fertilized egg would be XXY (from the egg with two X chromosomes fertilized by a Y-carrying sperm) and XO (from the egg with no X chromosome fertilized by an X-carrying sperm). Therefore, the only option that includes XXY and XO is choice D (XXY and XO).

During the Formation of Female Gametes, Nondisjunction of X Chromosomes