Transcript Biotechnology - Ms. Nevel's Biology Website

Biotechnology: Gel
Electrophoresis
Using the new to improve
the old…..
 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 some of 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
 Restriction enzymes can be used to cut a
strand of DNA into several pieces
 e.g., enzyme cuts when it encounters GAATTC
 A DNA fingerprint is a unique “picture” of a
person’s cut up DNA fragments that are then
separated by size
Who took Jimmy's lollipop?
The short version of how
DNA fingerprints are made
DNA is (-) charged. When you turn on the gel,
the DNA samples move across to the (+)
side.
Because the gel is porous (contains small
holes), large fragments get stuck and don’t
move far whereas small fragments move
farther.
Examples: Interpreting
DNA Fingerprints
Example 1: Who left the blood
stain? How do you know?
http://www.biologycorner.com/resources/DNAfinger.gif
Example 2: Who are the
children of these parents
http://www.scq.ubc.ca/a-brief-tour-of-dna-fingerprinting/
Example 3: Who is the father?
How do you know?
Example 4: Who are the
parents of this soldier? How do
you know?
http://www.glencoe.com/qe/images/b136/q4318/ch13_0_c.gif