DNA Basics Unit 6

What evidence categories does DNA belong to?

Indirect, physical, biological, individual, and trace

What are at least 4 forensics applications of DNA?

1. Match crime scene DNA with a suspect

2. Eliminate a suspect

3. Determine match to paternity, maternity or another relative

4. Identify a missing person

   and more

In what type of materials found at a crime scene can DNA be extracted from?

Biological materials such as blood, saliva, hair, skin and more

Step one of six in making a DNAP Profile/Fingerprint?

Obtain the DNA

Briefly explain step one: Obtain the DNA

Keep DNA dry and cool in storage, no direct sunlight

Step two of six in making a DNAP Profile/Fingerprint?

Extract and Isolate the DNA

Briefly explain step two: Extract and Isolate the DNA

Cells are isolated from biological evidence 

Cells are separated to release DNA

Step three of six in making a DNAP Profile/Fingerprint?

PCR (Polymerase Chain Reaction)

Briefly explain step three: PCR (Polymerase Chain Reaction)

Makes multiple copies of DNA

Step four of six in making a DNAP Profile/Fingerprint?

Use Restriction Enzymes

Briefly explain step four: Use Restriction Enzymes

DNA is mixed with special enzymes that will cut the DNA at specific sequences

Step five of six in making a DNAP Profile/Fingerprint?

Gel Electrophoresis

Briefly explain step five: Gel Electrophoresis

Electric current goes through the gel to separate fragments

Step six of six in making a DNAP Profile/Fingerprint?

Analyze DNA

Briefly explain step six: Analyze DNA

Look over the DNA

Step one of three in Polymerase Chain Reaction?

Denaturation

Briefly explain step one: Denaturation

DNA is untwisted to reveal pair sequences (A,G,C,T)

Step two of three in Polymerase Chain Reaction?

Primer annealing

Briefly explain step two: Primer annealing

Primers are added to DNA to locate complementary bases

Step three of three in Polymerase Chain Reaction?

Elongation

Briefly explain step three: Elongation

Complementary strands stick together making two new strands

What does CODIS stand for?

Combined DNA Index System

What is CODIS and how is it used?

 The FBI DNA database system. Unknown DNA from crimes scenes are put into CODIS, then compared to known criminal offenders already in the system.