How to Catch a Criminal with DNA and Gel Electrophoresis!

Have you ever wondered how scientists are able to match crime scene DNA to a suspect's DNA? Check out this video to see how scientists use gel electrophoresis to do DNA fingerprinting and catch criminals! Enjoy this clear, fun explanation of an important forensic technique!
Music: www.bensound.com
Transcript:
Have you ever wondered how scientists are able to match DNA from a crime suspect to DNA found at a crime scene?
One of the main techniques that makes this possible is Gel Electrophoresis!
Gel Electrophoresis, separates pieces of DNA based on their size, creating unique banding patterns for different individuals. But how does this work? Let’s find out!
Once you have obtained enough DNA from the crime scene and from your suspects, this DNA is cut with special enzymes called restriction enzymes. Each restriction enzyme cuts DNA at a very specific sequence called a restriction site. Since different individuals have different DNA, the location of these restriction sites varies. Therefore, different individuals end up with different sized fragments when their DNA is cut by restriction enzymes.
Now that we have these different sized fragments, we can do gel electrophoresis. The DNA from the crime scene and from each suspect is placed in wells in an agarose gel (a jelly-like substance with microscopic pores). This gel is located in a buffer-filled chamber that allows electrical charges to move. Notice that there is a positive end of the chamber and a negative end.
DNA moves toward the positive end when the chamber is turned on because DNA is negatively charged (opposites attract). But the DNA fragments don’t move at the same speed. Smaller fragments can move through faster because they can easily move through the pores in the gel. Bigger fragments, however, have a harder time moving through these small pores.
As an analogy, consider this obstacle course race. The small girl can run through quickly, the medium-sized guy is a bit slower, and the large bodybuilder is slowest because he gets stuck in the tube the most. For the same reason, smaller DNA pieces move through the pores in the gel faster but bigger pieces get more stuck and move slower.
The end result is a banding pattern, with small fragments making up the bands that travel farthest and large fragments making up the bands that don’t travel far. Because our suspects have different sized restriction fragments, their banding patterns won’t match each other. If, however, one of our suspects matches the crime scene pattern, this is good evidence that they were present at the crime scene.

[@newcreationfloraldesign8229]

So informative and fun! Well done Bioman.

[@BioManBiology]

Thanks!

[@katelynlivermore3596]

Thank you so much BioMan, this is perfect for my honors biology lab!

[@BioManBiology]

Awesome! I'm glad it is working for your class!

[@Stageaaaa]

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[@BioManBiology]

Thanks!

[@eshraksead4012]

That's a very good video. Thanx for the effort❤

[@BioManBiology]

Thanks, I'm glad you enjoyed it!

[@hamiltonbitches453]

only vid that actually helped thanksss!!!!

[@BioManBiology]

I'm glad to hear it helped! Thanks!

[@palvikumari7988]

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[@BioManBiology]

Thanks! I'm glad you enjoyed the video! All the best to you!

[@TheKyramSingleton]

thank you so much for this animation. beats class 100000000000% times

[@BioManBiology]

You're welcome, I'm glad you enjoyed it!

[@looshie6330]

but how do you know when it shows different spacing on all of them, like 1 is similar to the pattern of the crime scene DNA but not exact?

[@BioManBiology]

Could you clarify what you mean? Are you talking about on an actual gel where the lanes aren't always perfectly straight or lined up? There are several technical factors that can cause this. Here are some troubleshooting tips: gatescientific.com/technique-geeks-blog/f/agarose-gel-electrophoresis-troubleshooting-guide?blogcategory=Problem+Solving Does that help?

[@ahmedshoaib5658]

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[@BioManBiology]

Thanks!

[@user-xm8ct6ti4k]

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[@FGlava-28]

👍🏻

[@BioManBiology]

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[@xdte_]

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