The Arizona Hedgehog Cactus

The Arizona Hedgehog Cactus:
Endangered Species or not?

Lesson 8: Analysis of Data

Purpose: This is an opportunity for each student group to analyze the DNA banding patterns on their individual gels and then to pool the class data to come to an overall conclusion.

Time: One 50-60 minute class period

Materials Preparation:

Light box for viewing gels

Polaroid camera and film

Student Objective(s):

Analyze banding patterns for similarities and differences among individuals and between populations, as described below.

Lesson Plan:

Each group will remove their gels from the methylene blue dye and destain them (if ethidium bromide is not used).

Polaroid pictures of each gel will be taken and photocopied for dissemination to each group.

Each group will identify bands on the gel(s) which are suitable for scoring (bands are either unequivocally absent or present in each individual).

Suitable bands will be scored for absence (a "0") or presence (a "1) in each individual. Students record their data in a table for future reference.

Pair-wise comparisons can then be made of each individual to every other individual, counting the number of bands shared. Data should be recorded in a table.

Students may analyze the data in any other way they choose.

Note: The DNA profiles may also be analyzed using image processing programs such as NIH Image.

Supplemental Materials:

"Calculating Genetic Distances from RAPD Data" - Handout
"AZ Hedgehog RAPD Gels: Set 1" - data set
"AZ Hedgehog RAPD Gels: Set 2" - data set

The University of Arizona
Department of Biochemistry and Molecular Biophysics
General Biology Program for Secondary Teachers
warder@email.arizona.edu