Which of the following is not true of threshold traits?
A) Expression is significantly affected by environment
B) Genetic liability must cross a critical value for expression to occur
C) Monozygotic twins much more likely to both express such traits
D) Nature of genetic factors involved are poorly understood
E) They often show continuous variation in phenotype.

Question

Quizplus · Accepted Answer

Threshold traits do not typically show continuous variation in phenotype. Rather, there is a "threshold" value of liability that must be crossed in order for the trait to be expressed. Once this threshold is reached, the trait is either present or absent, without intermediate states.

Which of the Following Is Not True of Threshold Traits