Bio 100: Electrophoresis & DNA Fingerprinting
Which kind of DNA fragments do the bands at the top of the gel contain and which kind of DNA fragments do the bands at the bottom of the gel contain?
Bands toward the top contain large fragments of DNA while bands towards the bottom contain small fragments of DNA
How are DNA fragments fractioned (separated) through electrophoresis?
Based on size
What are sources of DNA that are typically found at a crime scene?
Blood, hair, skin and saliva
What kind of charge does DNA have?
DNA has a negative charge
Why does DNA move through the agarose gel during electrophoresis?
DNA has a negative charge and therefore migrates to the positive pole of the electrical field.
In what way does DNA migrate when an electric current is applied to the electric field?
DNA migrated to the positive pole (cathode) of the electric field.
What does the speed of migration of DNA depend on?
It depends on the size of the DNA fragment.
What is the role of the SYBER stain in gel electrophoresis of DNA?
It is a fluorescent dye that binds to and stains DNA, so that the bands of DNA can glow (under fluorescent light) and be seen
What does it mean to have hyper variable regions between individuals?
It means that no two individuals are gonna have the same nucleotide sequences in all of the hyper-variable regions
What fact is DNA fingerprinting based on?
The fact that there are regions in the human genome that are highly variable between individuals
How does the size of a DNA fragment affect the rate at which it travels through an agarose gel?
The smaller the fragment, the easier it will be for the DNA to move through the pores of the agarose gel, thus traveling faster.