Debbie Knight

Photo of the Week

In photo log on February 21, 2012 at 12:30 pm

This is a photo of an agarose gel (think really firm Jell-o) being placed on a ultraviolet light (UV) box which is making the gel “glow.”

The gel has been soaked in a dye that makes the nucleic acids visible (the dye: ethidium bromide actually binds to the nucleic acid and the UV light makes the dye-nucleic acid complex glow).

The nucleic acids in this case were amplified from a few strands of DNA during a procedure called a polymerase chain reaction (commonly called PCR) where a specific probe is used to copy only a certain region of the DNA over and over again until there is enough to see on the gel.

After the PCR is performed, the samples are loaded on one end of the gel, an electrical charge is applied across the gel, and the DNA moves toward the other end of the gel. Small pieces of DNA will travel farther in the gel than larger pieces (similar to how the small crumbs of potato chips seem to end up in the bottom of the bag — they can wiggle through all the spaces and move past the larger pieces).

If this PCR was performed successfully only one size (one band) of DNA will be seen on the gel (the pinkish-whitish stripe across the middle of the gel).

This photo was taken in my department’s Molecular Pathology Lab where diagnostic specimens are tested for genetic mutations.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: