Engaging the Student (Entry Task) 

Checking for Understanding (exit ticket)

1 class period

As an entry ticket, have students complete as many of the definitions as they can in the time allotted: 

• Entry Ticket: Lab Review & Vocabulary

• Comstock Gel Data
• Student Data Submission Form  
• Option 1:
• Student Handout 1: Size Approximation
• Student Handout 2: Analysis Follow-Up Questions 
• Option 2: Student Handout: Semi-Log Plot (analysis follow up questions included)
• Africa Maps: Country and Vegetation Information 

After students have digested their “ivory” DNA and performed their gel electrophoresis, they will need to analyze both their data and the data that we have now received from Dr. Comstock’s lab. The gels will need to be stained and de-stained at the beginning of, or prior to, this activity. Students can do this during class, or you may choose to do this outside of class.

There are 2 options for analysis of RFLP data from all sources of DNA:

• Option 1 – Calculation of RFLP lengths using banding patterns and size approximation. This involves estimating band or fragment sizes and is recommended for those whose classroom time is more limited or whose students are not as familiar with graphing.
•  Option 2 – Calculation of RFLP lengths using semi-log plot. This is recommended for students with strong math skills and tends to be slightly more time consuming.

You will need to choose the appropriate option for your students prior to beginning the analysis. For either option you choose, you will need to do the following:

1. Handout necessary materials for analysis. (Note: both options require a picture of the Comstock gel data and a Student Data Submission Form) 
2. Introduce the photograph of a gel from Dr. Comstock’s lab and the map of national parks in Africa, pointing out parks from which samples came, presence and reason for two ladders, and base-pair lengths for ladder bands.
3. Have students follow directions for generating base-pair length data from Dr. Comstock’s data using either option and record the base pair lengths on Student data submission form.  
4.  Have students obtain information about the country and vegetation regimes in Africa (Africa Maps Handout) for each park sample and record in the upper portion of the Student Data Submission Sheet.
5. Students should now work on their follow-up analysis questions; some of these could be done as an exit ticket and the remainder for homework is class time is limited. 

Student Materials: 

• Millimeter Rulers

Additional Teacher Materials: 

• Entry Ticket: KEY
• RFLP & Marker Sizes: KEY
• Data Submission Form: KEY
• 1 KB Ladder for RFLP Analysis