Bellringer: What does the term “biotechnology” mean? What does the word "forensics" mean?

Standard: Students will analyze how biological traits are passed on to successive generations. Element: Examine the use of DNA technology in forensics, medicine, and agriculture. EQ: How is DNA technology used to help investigators solve crimes (forensics)?

Biotechnology The use of living organisms and gene science to develop new products and new technologies to sustain life, fight crime and disease, and improve the environment. Provides improved food products. Provides medical advances to treat disease. Enhances the environment by providing new ways to prevent pollution and clean chemical and oil spills.

DNA forensics is the use of DNA to investigate criminal and legal matters. Every person (except identical twins) has a unique DNA sequence. So, samples of DNA can be compared to see if they came from the same person. These samples are cut, sorted, and tagged to produce a pattern of banding called a DNA fingerprint. DNA fingerprints are now used to confirm the identity of criminals, family members or dead bodies.

DNA Fingerprinting http://www.biotechnologyonline.gov.au/popups/int_dnaprofiling.html

Cutting the DNA into manageable fragments (the bands on the DNA fingerprint) Restriction enzymes recognize a specific sequence of DNA. The enzymes will cut DNA strands at all such sites. For example, whenever a restriction enzyme finds the DNA sequence: G A A T C, it will cut the DNA between the G and the A. Different restriction enzymes cut DNA at different sequences, so scientists can use them like scissors to cut a very long strand into smaller pieces.

Gel Electrophoresis After the DNA is cut with Restriction Enzymes, it is placed in a gel and an electric current is run through it. Since DNA is negatively charged, it will migrate down the gel to the positively charged end. Negative (-) Positive (+)

Gel electrophoresis The Shorter DNA fragments will move faster through the gel than the longer fragments. The result is a lane of fragments sorted by length. This method creates a DNA “fingerprint” that is unique to each person.

ELECTROPHORESIS Note that there are different types of gels and techniques for making DNA fingerprints. The “Southern Blotting” technique is illustrated in this video link:  http://highered.mheducation.com/sites/dl/free/0072835125/126997/animation40.html

Gel electrophoresis Which suspect is probably the attacker? Victim DNA #1 Control Suspect #2 Suspect #3 Suspect #4 Students should compare the bands and see that Suspect 3 most closely matches the attacker. Which suspect is probably the attacker?

PCR- Polymerase Chain Reaction Sometimes only a small drop of blood may be found at a crime scene and more DNA is needed to make a fingerprint. PCR is a process used to make many copies of a segment of DNA. PCR imitates the normal process of DNA replication in cells. PCR allows forensic scientists to use very small amounts of DNA to investigate crimes. Thermus aquaticus (Taq polymerase). Discovered in 1969 Yellowstone National Park near the lower geyser basin near Great Fountain Geyser and White Dome Geyser

The amount of DNA doubles with every cycle! PCR The amount of DNA doubles with every cycle!

Human Genome Project Completed in 2003

Benefits of Human Genome Project Improvements in medical prevention of disease, gene therapies, diagnosis techniques … Production of useful protein products for use in medicine, agriculture, bioremediation and pharmaceutical industries.