WFB 224 Conservation Biology
Hardy-Weinberg Problem set
Due Feb 6
1. Answer questions 2, 3, and 4 in the coursepack/handout Chapter 21
2. Which of the following population are in equilibrium? Show your calculations.
AA = 5, Aa = 70, aa = 25
AA = 38, Aa = 4, aa = 58
AA = 15, Aa = 49, aa = 36
AA = 26, Aa = 50, aa = 51
Do you notice anything interesting about these populations when you do the calculations?
(yes, there is a take-home lesson embedded in this question).
3. One factor that can result in non-equilibrium is a sampling mistake – two different populations
have been accidentally sampled together. Assume you know that one population has the
allelic frequencies A = 0.9 and a = 0.1, and the other has A = 0.2 and a = 0.8. Figure out
what the genotype frequencies would be in a sample of 200 animals if it contained 100
individuals from each population (in other words, calculate the genotype frequencies for each
population for 100 animals each, then add them together). Then do the H-W calculation for
the sample under the assumption that it is a single population.
What is the ‘clue’, when looking at the genotype frequencies of the sample, that something is
wrong – that it is unlikely to be in equilibrium?
Assuming this sample came from a single population, not two combined population, briefly
suggest one alternative explanation that could lead to the genotype frequencies you ‘observed’ in
this sample.