To produce an individual with Down syndrome (47,+21),
A) a nondisjunction event must have occurred during spermatogenesis.
B) more than one sperm must have been involved in fertilization.
C) a nondisjunction event must have occurred during oogenesis.
D) this must have been caused by uniparental disomy.
E) a nondisjunction event could have occurred during spermatogenesis or oogenesis.

Question

Quizplus · Accepted Answer

Down syndrome (47,+21) is caused by an extra copy of chromosome 21, which can result from a nondisjunction event during either spermatogenesis or oogenesis, leading to the production of a gamete with an extra chromosome.

To Produce an Individual with Down Syndrome (47,+21)