In the 1980s,when researchers began seeking gene variants that caused or contributed to bipolar disorder,it seemed that each extended family had its own mutations.These findings,looking back,most likely mean that
A)bipolar disorder results from imitating the behavior of an affected family member.
B)many gene variant combinations cause or contribute to bipolar disorder,but only a few such variants are seen in any one family.
C)many people fake the symptoms of bipolar disorder.
D)bipolar disorder reflects changes in gene expression,but not in mutations.

Question

Quizplus · Accepted Answer

The fact that each extended family had its own mutations suggests that bipolar disorder is caused by many gene variant combinations, but only a few such variants are seen in any one family. This supports the idea that bipolar disorder is a complex disorder with multiple genetic factors involved, rather than being caused by a single gene or mutation.

In the 1980s,when Researchers Began Seeking Gene Variants That Caused