TABLE 1

Two Exam Questions, One Mathematical and the Other Intuitive

The first question is a simple Hardy-Weinberg calculation question that most students will get correct. The second is a problem that many students get wrong because their intuition about population genetics has not caught up with their ability to calculate allele frequencies.
Question 1. Given that A is dominant to a, assume Hardy-Weinberg equilibrium and calculate the allele frequencies for a population of 3000 aa and 1000 A_ individuals.
Correct answer: p = 0.134, q = 0.866.
Question 2. Cockroaches in the Biology building were sampled and 3000 with long wings were found along with 1000 with short wings. Which trait is dominant?
Correct answer: You can't tell.
Common answer: Long wings (sometimes this answer is accompanied by a detailed explanation of Mendelian monohybrid crosses).