Population Genetics Indoor Experiment: Experiment Instructions (Lab Report)
MATERIALS NEEDED
Experiment Tracking Sheet: Earlobe Experiment Tracking Sheet.docx
Calculator (with square root function)
Determine Baseline p and q
Choose a source that contains lots of images or photos of DIFFERENT people such as Facebook, a televised concert or video recorded sporting event.
Identify the earlobe trait on at least 50 different people. Record how many had detached trait and how many had attached trait.
Determine the frequency of the recessive trait (q2). To do this, divide the number of
people with attached earlobe by the total number of people you counted.
Determine the frequency of the recessive allele (q). To do this, take the square root of the frequency you calculated in #3.
Determine the frequency of the dominant allele (p). This is equal to 1 – q.
You will need to repeat your observations on 50 more people in the next section.
Experiment – Earlobe Bias
You probably noticed a particular group of people that had a higher frequency of attached earlobes. It may be a particular age, race, gender, or even body shape.
(Hypothesis) Based on your observations, make a hypothesis about a group that will have different p and q values. Predict whether the q will be higher or lower than your initial observation and record this as a hypothesis. (Once you have made your hypothesis, DO NOT CHANGE IT. That is not ethical . . .)
(Identify Control Variables) Identify the earlobe trait on at least 50 people. Record whichever group category each belongs to (such as male vs. female or tall vs. short) along with their earlobe trait.
Determine p and q as above. Compare to the baseline p and q and
Conclusions – Was your hypothesis supported?
Earlobe Experiment Tracking Sheet
Do not turn this sheet in. It is for your data collection and notes when preparing a lab report.
Experiment 1: Baseline data to learn how frequent attached and free earlobes are overall in the human population
Experiment 2: Which group (race, gender, age, location, etc) has attached earlobes more/less often?
Calculating Hardy Weinberg Frequencies
Now you need to calculate the Hardy Weinberg p and q values for the BASELINE and EXPERIMENTAL datasets. The Hardy Weinberg equation is p2+2pq+q2=1.
The Hardy Weinberg equation has a rule where the dominant allele is always called p and the recessive allele is always called q. Do you remember which trait is dominant in this study?
p= ______________ earlobe allele
q=______________ earlobe allele
Since you do not know which people are heterozygous (have one dominant and one recessive allele) you will have to determine your HW values from people who are homozygous recessive (because you can SEE that they have the recessive trait from two copies of the recessive allele). The percent (as a decimal) of the homozygous recessive people out of the total number of people is q2.
Now for the numbers:
q2= number of homozygous recessive people in group divided by the total number of people in group
q= the square root of q2
p = since p+q = 1; p = 1-q
After you calculate your values for the baseline and each of the experimental groups, enter the information in the data table below.
Table X: describe what data is in the table description here
Number of Detached Number of Attached Total
Population p q
Baseline
Experimental Group 1 (describe here)
Experimental Group 2
(describe here)
