The threshold model has been proposed to explain situations in which
A) a small number of genotypes can produce a wide range of phenotypes.
B) a wide range of genotypes can produce a limited number of phenotypes.
C) environmental factors only affect individuals.
D) a simple trait can produce a wide range of phenotypes.
E) environmental factors do not have an influence on phenotype.

Question

Quizplus · Accepted Answer

The threshold model suggests that a wide range of genotypes can produce a limited number of phenotypes, which means that environmental factors play a significant role in determining the phenotype. Under this model, individuals have a threshold level of genetic liability for a particular trait, and once that threshold is exceeded, the trait will be expressed in the phenotype. Therefore, the phenotype will only be expressed in individuals who have a genetic liability exceeding the threshold, regardless of the specific genotype they have.

The Threshold Model Has Been Proposed to Explain Situations in Which