A man with trisomy 21 could pass Down syndrome to offspring if he
A)produces sperm that have two copies of chromosome 21.
B)produces sperm lacking chromosome 21.
C)also has Turner syndrome.
D)is a carrier of a deletion for chromosome 21.

Question

Quizplus · Accepted Answer

A man with trisomy 21 has three copies of chromosome 21 instead of the usual two. If he produces sperm that have two copies of chromosome 21, instead of the typical one, and the egg also has a copy of chromosome 21, the result will be a zygote with three copies of chromosome 21 - Down syndrome.

A Man with Trisomy 21 Could Pass Down Syndrome to Offspring