BIOTECHNOLOGY GEL ELECTROPHORESIS Our knowledge of the structure

BIOTECHNOLOGY: GEL ELECTROPHORESIS

• Our knowledge of the structure and function of DNA is fairly new information. • Watson & Crick - 1953

• However, in a short amount of time, our DNA knowledge has been used to: • Improve Identification Methods of Criminals • Determine Maternity/Paternity • Bioengineer products

• Blood typing was first used for these purposes, but it has limited capability because it is not specific to each person.

Gel Electrophoresis (DNA Fingerprinting) • Every person has a unique sequence of DNA. • DNA fingerprint- A ‘picture’ of a person’s DNA fragments that are separated by size

• Scientists can make a huge amount of identical DNA from a small sample using a process called PCR (polymerase chain reaction) • Enzymes are used to cut a strand of DNA into several pieces.

How DNA fingerprints (Gel Electrophoresis) are made 1) Restriction Enzymes: The enzymes cut the DNA into fragments at a specific DNA sequence. (Ex. AATT) This produces DNA fragments.

2) The Gel: Thicker than Jell-O. Molded with wells (holes) in one end. DNA fragments are placed in the wells.

3) An Electric Field: The gel is placed in a solution. An electric field is applied, making one end of the gel negative and one end positive.

4) The Fragments Move: The negatively-charged DNA fragments travel towards the positive end. The smaller the fragment, the farther it moves through the gel. The smallest fragments move the farthest from the wells.

Determining Parents http: //www. scq. ubc. ca/a-brief-tour-of-dna-fingerprinting/

Example 1: Who left the blood stain? How do you know? http: //www. biologycorner. com/resources/DNAfinger. gif

Example 2: Who are the parents of this soldier? How do you know? http: //www. glencoe. com/qe/images/b 136/q 4318/ch 13_0_c. gif

Simulating Gel Electrophoresis - Give out worksheet Who took Jimmy's lollipop?