Purpose:
You will create a DNA fingerprint in order to determine whether the suspect in the
scenario is guilty or innocent. Using pop beads and connectors, students create
linear DNA molecules that represent alleles of a VNTR region of human genomic
DNA. Through simulated restriction enzyme digests, both alleles are cut into
smaller pieces. VNTR alleles are detached from the surrounding DNA sequence.
The digested fragments are separated by simulated gel electrophoresis on paper
gels.
Procedure:
Groups of four, with students working in pairs within each group
DNA Assembly
Need: red, purple, orange, yellow, blue, and green colored pencils (one set
per group)
1. One pair in each group of four will work with DNA Sample 1,
and the other with DNA Sample 2.
 Represent different alleles of a VNTR region of
human genomic DNA extracted from blood given by
victim
2. color the appropriate template diagram for your two-person
team to reflect the molecules as described in the key
 refer to the key
3. In pairs, assemble either DNA Sample 1 or 2, in
accordance with the template
4. once completed, check the structure created by the other
pair in your group against the template
5. Have instructor check your work
Restriction Enzyme Digestion
1. For each DNA sample, perform a simulated restriction
digest with the Hae III restriction enzyme
2. Locate the Hae III recognition sites
3. Draw a line to indicate where and how the enzyme will cut
4. Have instructor check your diagram before you continue
5. Carefully break the DNA molecule models apart at the Hae
III restriction enzyme cutting sites (use your template as a
guide
6. Fill in the following table according to the results obtained
after the simulated restriction enzyme digests
 For each student pair: count the number of base
pairs in each of the fragments in your sample and
record the number of fragment sizes (from left to
right) in the appropriate row of the table below. In the
last column of the table, record the number of times
you find the sequence TG (thymine, guanine (yellow,
green)) repeated in the top strand.
DNA Fragments Results
DNA
Sample
Total # of
restriction
sites
Total # of
fragments
obtained
Size of
fragments (# of
paired bases)
# of TG repeats
Sample 1
Sample 2
Paper Gel Diagram
7. Each two person team obtain a paper gel
8. place the paper with the negative end at the top and the
positive end at the bottom
9. line up the three DNA fragments from your sample on the
paper, based upon their base-pair size
10. record your results by drawing a line at the appropriate DNA
marker position for each fragment (draw the line where the
hydrogen bonds connect complementary base pairs)
11. check with instructor when done
12. compare your results to the victim and suspect paper gel
produced by the instructor to see which sample yours
combines with