BIOL 471
Name ________________________


Take-home Quiz (Population Genetics, Chap. 5 and 6) – open book, work alone
Due no later than 1:30 pm Monday February 21, 2005

1. (2) The Hardy-Weinberg equation is used to determine allele frequencies and genotype frequencies in a population in the absence of evolutionary forces.  What evolutionary forces might cause these frequencies to deviate from equilibrium?
 
 
 
 

2. (2) A human trait (say the ability to taste PTC), is controlled by a dominant allele A, and has a frequency of 0.6 in a population, and there is only one alternative allele (a for the inability to taste PTC).  If the population is in Hardy-Weinberg equilibrium, what are the frequencies of each of the following genotypes?

a) homozygous dominant (AA) tasters

b) heterozygous (Aa) tasters

c) homozygous recessive (aa) nontasters
 
 


3. (2) In a sample of redbacked voles, the following three blood protein genotypes were observed:

 MM 123
 MJ 530
 JJ 129
Calculate the genotype frequencies.
Calculate allele frequencies for M and J.
Are the observed genotype frequencies in Hardy-Weinberg equilibrium?
Briefly explain your answer (i.e., how do you know they are in equilibrium, and if they are not in equilibrium, why not?).
 
4. (2) It has been suggested that recessive genetic diseases like cystic fibrosis persist in human populations not because of mutation-selection balance, but by a form of heterozygote superiority or overdominance.  Explain how you could tell the difference between maintenance by mutation-selection balance and maintenance by overdominance, and mention what the evidence is in the case of cystic fibrosis in humans.
 
 
 
 
 

5 (2) Answer problem 2 on page 248 in the text.  It makes reference to a paper published in Nature Genetics, a pdf file of which you can access here.  The title of the paper should shed light on the answer to the question.