Question

Which of the following statements regarding human genetic disorders is accurate?

a. Nondisjunction is responsible for causing Huntington's disease.
b. Disorders in individual genes can cause disease or provide individuals with a genetic advantage.
c. Nondisjunction can lead to an incorrect number of sex chromosomes.
d. Disorders in individual genes are responsible for Down's syndrome

Answer 1

d. Disorders in individual genes are responsible for Down's syndrome

Which of the following statements regarding human genetic disorders is accurate?
NOT:
a. Nondisjunction is responsible for causing Huntington's disease.
b. Disorders in individual genes can cause disease or provide individuals with a genetic advantage.
c. Nondisjunction can lead to an incorrect number of sex chromosomes.

Answer 2

The correct answer is (c) Non disjunction can lead to incorrect number of sex chromosomes.

Non dis junction can occur during meiosis 1 or meiosis 2 with different results. If the disjuction occurs then the chromosome pair does not separate in equal numbers during fertilization and it results in abnormal chromosome number. It can sometimes results in trisomy or sometimes this can result in monosomy.

Example: Klinefelter syndrome in which trisomy occurs. In this syndrome the male have an extra X chromosome.