SIZING UP DNA
Grades 9-12

DNA restriction analysis is a fundamental concept in the field of biotechnology. Learning the techniques and protocols involved in restriction analysis can be made more interesting and meaningful if placed in the context of a murder mystery simulation. This lesson and video introduces students to the process of electrophoresis and restriction enzymes and the equipment involved in DNA fingerprinting.
The lesson can be followed by an actual simulation if equipment is available.

NOVA: Murder, Rape, and DNA

Students will:

• understand the functions of the equipment used in DNA restriction analysis.
• recognize and understand the following words: electrophoresis, restriction enzymes.
• be able to analyze DNA fragments to determine size.
• be able to differentiate between the usage of standard vs. semilog graphing.

• Student Worksheet
• Crime Scene Lab Sheet (optional)
• Restriction Digest Gel or Photograph
• Sizing-up DNA Sheet
• Semi-log Graphing Paper
• Metric Ruler

Show students samples of the equipment used in the study of DNA fragments. Students will be provided with a worksheet picturing the equipment. They will write a description of what they believe each of the pieces is used for. Ask the students, "Can you tell, by just looking, how each of these objects are used?"

View NOVA: Murder, Rape, and DNA
Segmented viewing: The video should be cued 40 minutes into the program. Find the segment where scientists are shown using electrophoresis equipment as part of a murder mystery. Provide the students with a brief background of information about the video prior to this segment. START the tape at the where Pitchfork's impersonator is having a blood sample drawn. After the blood is drawn, the technicians perform tests. Show the segments with the sound off which allows students to visually focus on the equipment and how it is used. PAUSE after each piece is shown in use. Direct students to record functions. STOP the segment when the completed DNA fingerprints are shown (about 3 minutes).
Second viewing: REWIND and show the same segment again, this time with the sound on. Direct the students to focus on listening for the vocabulary terms on their worksheet. Tell the students to raise their hands when they hear each word defined. Teacher pauses after each term has been defined to allow students to write definitions.

Teacher will facilitate discussion concerning the functions of the biotechnology equipment and the definitions of the terms electrophoresis and restriction enzymes. as demonstrated in the video.

Sizing - Up DNA
The gel (or photograph of gel) shows samples of DNA from the bacteriophage lambda, cut using agarose gel electrophoresis. The DNA samples were loaded into the wells (holes) in the agarose gel and electrophoresed. An electric field applied across the gel causes the DNA fragments to move from the wells through the gel, toward the positive electrode. Smaller DNA fragments migrate faster than larger ones, so the fragments of differing size become concentrated in separate bands. The characteristic number and pattern bands produced by each restriction enzyme could be a "DNA Fingerprint".
Classes performing lab with actual gels will have five lanes of fragments (fingerprints), while those using a photograph will have four. In either case students will graph lane #3, read from left to right with the wells at the top. Lane #3 in each case contains lambda DNA cut with HIND III enzyme. Students can use this information from this graphing to interpolate fragment size for each of the other lanes.
Crime Scene Simulation
Gel Set-up
____________________________________________________________________
#1 #2 #3 #4 #5
Hind III/DNA
Uncut DNA
Hind III/DNA
Ban HI/DNA
Eco RI/DNA
Please Note:THESE WORDS SHOULD LINE UP VERTICALLY UNDERNEATH EACH #

DNA restriction analysis is a fundamental concept and practice in recombinant DNA technology. The ability to cut DNA predictably and precisely enables scientists to manipulate and recombine DNA. The discrete bands of like-sized DNA fragments in each lane shows that each of the DNA molecules present in each restriction digest were all in precisely the same place (a fundamental concept behind DNA fingerprinting).

Direct students to research and contact biotechnology companies operating in locally or nationally. Some companies will allow their scientists to correspond with students. Determine what special academic preparation is needed for a career in this field.
Contact and interview forensic scientists who collect evidence at the crime scene.

• Students can research a broad diversity of topics in biotechnology by visiting the About Biotechnology site on the internet. The site has categories which include:
  • Biotech chronicles
  • Unlocking the technology
  • Putting the science to work
  • The career center
  • The graphics gallery

Research topics for students include:
1. Describe the historical development of
biotechnology.
2. What are the current techniques, methods, and
equipment used in biotechnology?
3. How is biotechnology currently being used and developed in science, agriculture, medicine, and industry?
4. What career opportunities exist in the field of biotechnology? How does a student prepare for this job market?
About Biotechnology
http://www.gene.com/ae/AB/

• BioOnline: Biotechnology On The 'Net provides students with resources to investigate the corporate world of biotechnology. Listings include name, location, and product line of corporations involved in the biotech industry. Information on this site includes government, research, and educational applications of biotechnology.

Research projects for students include:
1. List the 10 corporations which are located closest to your school. Include their names, location, product, and general description of the company.
2. List 10 career opportunities available in the biotech industry. Include a brief job description and the educational requirements of the job (students may also use About Biotechnology listed in extension #1).
BioOnline: Biotechnology On The 'Net
http://cns.bio.com/

• Use Court TV on-line services to determine the legal status of DNA fingerprinting use in the courtroom.

Transcripts of the OJ Simpson case are currently available on-line.
RESOURCES
BIO RAD Equipment
2000 Alfred Noble Drive
Hercules, California 94547
(510) 741-6746

Master Teachers: Stan Hitomi and Randall Lam