Polymerase Chain Reaction (PCR)

Polymerase chain reaction (PCR) allows researchers to amplify DNA in a test tube. This process uses an enzyme derived from heat-resistant bacteria. The steps of PCR are driven by changes in temperature.
TRANSCRIPT: Polymerase chain reaction (PCR) is a process where many copies of a specific piece of DNA can be made. This is known as amplification. Double-stranded DNA (red) unwinds and separates when the temperature is increased. As the temperature is decreased, small starter sequences called primers (glowing) can attach or anneal to the DNA. These primer sequences are usually only 20 to 25 nucleotides long, and are designed to match the start and end points of the DNA piece to be amplified. Once the primers have annealed, Taq polymerase (blue) copies the DNA starting from the primer. The temperature is increased; the strands separate; more primers anneal; the DNA is copied; and this cycle is repeated many times. In a typical PCR reaction there are 30 cycles, which can potentially create one billion copies starting from one molecule of DNA.

[DNALearningCenter]

Visit us in Cold Spring Harbor, Brooklyn, or Sleepy Hollow!

[EDUARDO]

This video is by far the best PCR video I have seen. Incredible work and accuracy impart of the people that dedicated their time for creating this animation.

[crazyzombie]

A little note: the annealing temperature is usually chosen between 40-60°C. There are a few factors that influence the annealing temperature. An important factor is the fact that G-C binding involves 3 hydrogen bonds (rather then 2 hydrogen bonds at A-T binding). Because of these 3 hydrogen bonds, the more G's en C's are in the primer, the stronger it will bind to its complementary sequence on the template DNA. Therefore higher annealing can and must be used when the primer contains lots of G & C. (The annealing temp. can even go up to 72°C if you have a high G-C content)

[alimatinv]

this incredible animation is by far the most comprehensible animation about PCR that I've ever seen. thank you

[AmruMagdy]

Impressive. You obviously put a lot of time into this video. Thank you for new information.

[MediaBuster]

Best explanation ever!! No music, no long meadering.

[Birdietweettweettwee]

There are 2 primers for each target sequence: forward and reverse. Since they are each in the forward and reverse direction, they act kind of like parentheses in the DNA for amplification.

[mcarson]

If you know the sequence of DNA that you are trying to amplify then you can design a primer to specifically bind to that sequence, by have bases that are complimentary. It just requires knowledge of the sequence first.

[ShyaamHaridasTHEHERO]

Amazing animation.
I was able to understand how the gene of interest is being amplified

[crawdad]

So clear. So easy to understand, simple but effective animation and coherent explanation. Very well done, thanks.

[TheMcardarelli]

Best explanation on Youtube! The notes, the animation, easy to get and understand ;)!

[FoftheCs]

the single strands at the beginning each have different sequences of bases. you need two sets of primers to bind to each one. you add the primers in excess though to make sure that the primers bind. pcr usually stops when the primers run out and you can either add more primers and continue the process or stop there.

[dcdean]

It sounds like you understand this stuff pretty well. Assuming you've determined the target sequence you want to amplify, how does one determine which two primers to use?

[Narkodrom]

@zanderez
No, its DNA strand which is being separated. RNA is usually single stranded. Remember simple rule? DNA is used to make RNA, which in turn, is used to make proteins.

[Birdietweettweettwee]

Depending on the sequencing machine downstream that you will use, the gc content of the amplicon, different computational softwares will pick the perfect pair of primers about 20 base pairs long compatible in melting temperature for amplification.

[Bbita]

Perfect animation and perfect explanation.
Thanks for sharing :)

[ashokkushwaha]

This is simply superb One of the most easy and complete explanation of PCR amplification process. well

[sanashaikh]

Dis was by far d most simplest n tym saving video thnk u so much

[MediaBuster]

Thank you Kary Mullis for creating this. May your soul R.I.P.

[ajshawn]

I love you so much, I finally understood the concept of primer