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Overview• Gel Electrophoresis is a process that can be used to separate DNA Fragments• It uses an electric current to separate the pieces of DNA that are run through the gel• The gel used has agarose, a highly purified seaweed, in it.• It can separate DNA molecules from hundreds of nucleotides to hundreds of thousands of them.
Submerging the Gel• First, a salty solution is poured over the gel in order to conduct electricity.
Loading the Samples• The DNA samples, colored with blue loading dye, are placed in the slots made in the agarose gel.
Running the Gel• Since DNA has a negative charge, it will move toward the positive end of the gel tank when electricity is run through the solution.• The way in which it moves is called reptation, because it moves like a snake through the porous gel.• Smaller fragments move faster and further than larger fragments, allowing for separation.
Recording the Results• After the gel has been run, the ethidium bromide that was added to it causes the gel to glow under ultraviolet light.• While it is glowing, a picture can be taken of it to record the results
How It Changed Science• Gel Electrophoresis affected science in a big way.• Scientists now had a relatively easy and definitive way to test and compare DNA samples.• It lead the way for more specialized and complex DNA testing.
Forensics• Gel Electrophoresis has become an absolute necessity in the field of Forensics.• It allows them to obtain an irrefutable link to a possible suspect, or anyone in general.• The DNA fingerprint it produces is also very useful in paternity testing.
Advantages• Gel electrophoresis has some advantages:• Provides a clear link between similar results• Relatively simple to perform• Can test DNA from any type of evidence (hair, blood, skin, etc.)• Relatively inexpensive
Disadvantages• The disadvantages of gel electrophoresis are:• The gel can be altered and provide inaccurate results.• User error can be catastrophic, depending on the mistake
Ethical Concerns• There are very few ethical concerns with gel electrophoresis, as it is only a process by which you can obtain DNA evidence, and is usually only used for the good of society, such as crime fighting, suspect identification, paternity testing, etc.