Which of the following sets of individuals had the highest concordance for MDD and what does that tell us?
A) Monozygotic twins raised together had only slightly higher concordance for MDD than monozygotic twins raised apart. This indicates a strong genetic component to the disorder.
B) Monozygotic twins raised together had a higher concordance for MDD than monozygotic twins raised apart. This indicates the importance of nonshared environmental factors as primary in the development of the disorder.
C) Dizygotic twins have a higher concordance rate for MDD than monozygotic twins, whether raised together or raised apart. This indicates there is a strong genetic component to the disorder.
D) Twins had to have been raised together to show any concordance for MDD above that of typical siblings. This indicates a relatively small genetic role in MDD.

Question

Quizplus · Accepted Answer

The fact that monozygotic twins (who share all their genes) have a higher concordance rate for MDD than dizygotic twins (who share only 50% of their genes) indicates a strong genetic component to the disorder. The fact that the concordance rate is still higher for monozygotic twins raised apart (who share their genes but not their environment) than dizygotic twins raised together (who share their environment but not all their genes) further supports the genetic component of MDD.

Which of the Following Sets of Individuals Had the Highest