Hardy-Weinberg problem set

Hardy-Weinberg Theorem states that if a population is NOT evolving then the frequencies of the alleles in the population will remain stable across generations - it is in equilibrium.

We can use the Hardy-Weinberg equation to make predictions about the relative frequency of the different alleles (as well as the associated genotypes), even if there is population growth, as long as the five conditions we discussed in class hold true. Think about what those five conditions are.........

Alternatively, Hardy-Weinberg equation can be a means to determine if a population is indeed evolving - that the allele frequencies are changing and therefore NOT at equilibrium.

The trick to using the Hardy-Weinberg equation to help evaluate the frequency of a particular allele frequency at time X, or to make a prediction about the frequency of a particular genotype/phenotype in future generations, is to go through the math is a step-by-step manner.

For the problems below assume all genes have only two alleles and there is a simple dominant recessive relationship.

-------------------------------------------------------------------------------------------

NOTE -- I am not necessarily asking the questions in the order in which you should answer them, given the step-by-step approach.

1. Lets say that brown fur coloring is dominant to gray fur coloring in mice. If you have 168 brown mice in a population of 200 mice........

What is the predicted frequency of heterozygotes?

What is the predicted frequency of homozygous dominant?

What is the predicted frequency of homozygous recessive?

------------------------

2. If 81% of a population is homozygous recessive for a given trait..........

What is the predicted frequency of homozygous dominant?

What is the predicted frequency of heterozygotes?

What is the frequency of the dominant and recessive alleles in the population?

------------------------

3. If 51% of the population carries at least one copy of the recessive allele.......

What is the predicted frequency of individuals in the population that express the dominant phenotype?

What is the predicted frequency of individuals in the population that express the recessive phenotype?

ANSWERS -- work through the problems first! Remember to always double-check yourself by adding the frequencies of the three genotypes.