After reading the paragraphs below, answer the questions that follow.
Mr. and Mrs. Smith have three sons in elementary school. Two of their children are progressing normally, but their youngest son, Charles, has been much slower than his siblings in developing speech and language skills. His parents are concerned that he has a learning disability and decide to investigate further. Since some learning disabilities can be genetically based, their pediatrician recommends a chromosomal analysis.
The results show that Charles has a trisomy of the sex chromosomes, diagnosed as XYY, which is caused by nondisjunction in the formation of the father's sperm. The nondisjunction resulted in an extra copy of the Y chromosome. The extra copy was passed on to Charles during fertilization. Most often, this chromosomal change causes no unusual physical features or medical problems, but those with trisomy of the sex chromosomes do have a higher than normal risk of delays in learning development.
-If Charles gets married and starts a family, which of the following chromosomal abnormalities has an increased chance of occurring in his children?
A)YO
B)YY
C)XO
D)XXY

Question

Quizplus · Accepted Answer

Charles has an extra Y chromosome (XYY). If he has children, there is a chance he could pass on the extra Y chromosome, resulting in XYY in male offspring. This condition does not occur in females, so choices A, C, and D are not possible. Choice B (YY) is also not possible as it would require Charles to contribute two Y chromosomes, which is not biologically possible as males only have one copy of the Y chromosome.

After Reading the Paragraphs Below, Answer the Questions That Follow