If the concordance rate between identical twins is less than 100 %, what does this imply?
A)Concordance rates are difficult for researchers to calculate; a lack of 100% concordance reflects experimental error.
B)Concordance rates are estimates and can be only measured if one of the twins shows the trait.
C)Concordance rates less than 100% reflect environmental effects on the trait.
D)Concordance rates are estimates of genetic influence only.

Question

Quizplus · Accepted Answer

If the concordance rate between identical twins is less than 100%, it implies that there are environmental factors influencing the trait. The fact that the twins have identical DNA but do not both express the trait suggests that there must be some external factor affecting its development.

If the Concordance Rate Between Identical Twins Is Less Than