Biotechnology Intro & Gel Electrophoresis

DNA Forensics

Based on what you know (from T.V., reading, or other sources), how do forensic scientists use DNA to solve crimes? Use your knowledge of DNA and base sequences to formulate your answer. Answer in complete sentences!

Sentence starter: Forensic scientists may use DNA to solve crimes by…

What does…

• BIO- mean?

• TECHNOLOGY?

SO….

What is BIOtechnology Anyway????

• Manipulating living organisms using various types of technology to produce more useful qualities:– Using better genes and traits• Allows the best or desired traits to be expressed.

Research in Biotechnology1. Help humans create crops that can be frost resistant2. Use transgenic organisms to help medical

researchers model human physiology for testing3. Help industryto create bacteria to break

downpollutants into harmless products4. Pharmaceutical companies use recombinant DNA to

cheaply produce human hormones (insulin) and other proteins

5. Help solve crimes and determine familial relationships

One of the ways is the same way Maury tests for the father…

Gel Electrophoresis

• A method used in biochemistry and molecular biology to separate DNA or RNA molecules by size to compare DNA data.

Also known as…• A DNA Fingerprint• DNA Fingerprinting/Gel Electrophoresis:

http://www.youtube.com/watch?v=PSwlCk_Z02c&feature=related

• Copy these Questions:• Write the steps used in Gel electrophoresis: • Where would you find the shortest stand of

DNA? • What causes the fragments on DNA to move?

What can this be used for?• Paternity Tests

– Who is the father?

• Familial Relationships– Who is the mother?– Who are the siblings, cousins, grandparents, etc.?

• Evolutionary Relationships– How closely related are two organisms (humans & apes)?

• Crime Scene Investigations– Who committed the crime?

GelElectrophoresis

Basic Steps..

1. Extract DNA sample

2. Cut DNA into smaller pieces using Restriction Enzymes

3. Put the smaller DNA fragments into the Gel Tray

4. Use a Charge to separate the pieces of DNA

5. fAnalyze the DNA fragments

Goal of Gel Electrophoresis

1. The process of Gel Electrophoresis works to separate and analyze DNA fragments according to their size & shape.

2. In order to cut the DNA into fragments, restriction enzymes are used. – These are specific enzymes (proteins) that

recognize specific sequences of DNA and then cut it in half.

Goal of Gel Electrophoresis

3. Samples of DNA fragments are loaded onto a GEL ELECTROPHORESIS.

4. DNA fragments move in the Gel due to opposite charges (DNA is negatively charged)– The SMALL strands move further down the Gel

than the LARGER strands of DNA.– Since they are larger and heavier, the LARGER

strands do not move as far down the Gel

Goal of Gel Electrophoresis

5. The groups of DNA fragments show up as small lines in the Gel

6. Now a DNA FINGERPRINT is created, which can be analyzed.

What can this be used for?• Paternity Tests

– Who is the father?

• Familial Relationships– Who is the mother?– Who are the siblings, cousins, grandparents, etc.?

• Evolutionary Relationships– How closely related are two organisms (humans & apes)?

• Crime Scene Investigations– Who committed the crime?

Let’s Take a look…

• http://www.youtube.com/watch?v=PSwlCk_Z02c&feature=related

Check Point

1. Write the steps used in Gel electrophoresis:

2. Where would you find the shortest stand of DNA?

3. What causes the fragments on DNA to move?

Gel Electrophoresis

Gel Electrophoresis

GelElectrophoresis

DNA fingerprinting applications

Sample Problems

Practice

Blood on Knife Victim Suspect A Suspect B

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Practice