Human Genetics: A Worldwide Search for the Dominant Trait

Activity 3: Data Analysis

Materials

Final "Verified" Data reported from all the participating schools (available from the Project Data section).
NOTE: check Project Instructions for Availability
Graph paper or Spreadsheet Program (i.e. Excel)
Student worksheet

Teacher Instructions

If you are not going to have students working at computers, you should print enough copies of the data and the student worksheet for each group to have one copy of all the data and each student a copy of the student worksheet. Then separate students into groups of 2 or 3. Assign each group 1 or 2 traits. Each group will also need a calculator. Give each group 15-25 minutes to answer the questions or as you see fit. Afterwards each group should report their findings to the class.

If you have enough computers so that students may work 1 or 2 to a computer, then have students download the data from the website at http://www.ciese.org/curriculum/genproj/project_data.html. Once they have the data in Microsoft Excel, they can then manipulate the chart and answer the questions below or in the student worksheet for all traits. If time permits, have students create charts in Excel and then use them in Microsoft Word to submit their final report.

Download the Data

Go to the Project Data section of this web site and download the final "Verified" data. You can select to download the data (recommended) in a Microsoft Excel or ClarisWorks spreadsheet file for the PC or Mac or you can alternatively view it as a web page.

It is recommended that you use the ''verified" data for your analysis. This data has been checked and verified by the project leader. Using this data will ensure that when students analyze the data they will not be mislead by any unreasonable, unverified, or incorrect data. However, comparing the "unverified" database to the "verified" database might be a good exercise for advanced students. They could determine if all the "unverified" data makes sense. Scientists NEVER throw out data without looking into why there might be strange results and this might be a good lesson for your students. You are welcome to use the project Discussion Area to question other students about their results and to provide recommendations to the project leader about what to do with "questionable" data.

Basic Data Analysis

Now that you have downloaded the checked data, you are ready to determine what the

Here are some general guidelines:

Key question: How often do certain easily-observable human traits occur?
1.	For each of the seven traits surveyed, calculate the total number of individuals surveyed.
2.	For each of the seven traits surveyed, calculate the total number of individuals exhibiting the dominant trait.
3.	For each of the seven traits surveyed, calculate the total number of individuals exhibiting the recessive trait.
4.	Calculate the percentage of students who have each of the phenotypes surveyed.

Key question: Do most people have the dominant traits? Is the dominant trait most prevalent?
5.	For one of the traits surveyed, what are the possible phenotypes for individuals showing the dominant trait?
6.	For one of the traits surveyed, what are the possible genotypes for individuals showing the recessive trait?
7.	Are the dominant traits always the most common in a population? Explain your answer using data to support it.
8.	What might cause a recessive trait to be more common in a population?

Extention Analyses

These analyses were recently developed as extension activities to the Basic Data Analysis. Some activities are more advanced that others. Depending on time and grade level you should consider implementing one or more of the Optional Analyses in your classes.

How do you know the dominant trait is dominant?

Why isn't the dominant trait most prevalent?

Is red-green color blindness in humans an inherited trait?

What percent of the population is heterozygous dominant for one of the traits?

Is evolution occurring in humans?