Population Genetics and Evolution
By: Kevin Zamar
Group Members: Brandon Torres, Anh Tran
Purpose: The purpose of this lab is to learn about the Hardy-Weinberg law of genetic equilibrium and to study the relationship between evolution and changes in allele frequency by using your class to represent a sample population.
Hypothesis: I predicted that a majority of our population (class) will be able to taste the PTC paper.
Materials: Small population (class), PTC paper, Allele cards
EXERCISE 8A: Estimating Allele Frequencies for a Specific Trait within a Sample Population
1. Using the PTC taste-test papers provided, tear off a short strip and press it to your tongue tip. PTC tasters will sense a bitter taste. For the purposes of this exercise these individuals are considered to be tasters.
2. A decimal number representing the frequency of tasters should be calculated by dividing the number of tasters in the class by the total number of students in the class. A decimal number representing the frequency of nontasters can be obtained by dividing the number of nontasters by the total number of students. You should then record these numbers in Table 8.1.
3. Use the Hardy-Weinberg equation to determine the frequencies of the two alleles. The frequency q can be calculated by taking the square root of q2. Once q has been determined, p can be determined because 1 – q= p. Record these values in Table 8.1 for the class and also calculate and record values of p and q for the North American population.
EXERCISE 8B: Case Studies
CASE I – A Test of an Ideal Hardy-Weinberg Population
1. Turn the four cards over so that the letters do not show, shuffle them, and take the card on top to contribute to the production of the first offspring. Your partner should do the same. Put the two cards together. The two cards represent the alleles of the first offspring. One of you should record the genotype of this offspring in the...