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The X and Y chromosomes pair in meiosis at the pseudoautosomal regions. A nondisjunction of the X and Y chromosomes in a male during meiosis I would produce which of the following combinations of gametes?

(A) one sperm with two X's, and three sperm with Y's
(B) two sperm with two X's and two sperm with two Y's
(C) one sperm with no X's, and three sperm with an X and a Y
(D) a sperm with two X's, a sperm with two Y's, and two sperm with no sex chromosomes

1 Answer

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Final answer:

The result of a nondisjunction of the X and Y chromosomes in a male during meiosis I would be the production of four unique gametes: one sperm with two X chromosomes, one sperm with two Y chromosomes, and two sperm with no sex chromosomes.

Step-by-step explanation:

The question at hand involves the consequences of nondisjunction of sex chromosomes during meiosis. Nondisjunction is an error in cell division that results in gametes with an abnormal number of chromosomes. Specifically, during meiosis I, if the X and Y chromosomes fail to separate properly, it can lead to four unique gametes. Two of these gametes will have two copies of one sex chromosome (either XX or YY), and two will lack a sex chromosome entirely. Thus, the correct option is: (D) a sperm with two X's, a sperm with two Y's, and two sperm with no sex chromosomes.

This scenario paints a picture of the unique but problematic outcomes of meiosis when nondisjunction occurs. It's important to remember that in typical meiosis without errors, gametes with a single sex chromosome are produced. However, nondisjunction disrupts this balanced assortment, potentially leading to conditions such as monosomy and trisomy.

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