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.
Originally created for DNA Interactive ( www.dnai.org ).
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]

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[@EDUARDO12348]

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.

[@yusufnash13]

i realize I am kind of off topic but do anybody know of a good site to watch newly released tv shows online?

[@elishajoaquin218]

@Yusuf Nash Flixportal :P

[@yusufnash13]

@Elisha Joaquin thanks, I signed up and it seems like they got a lot of movies there :) I really appreciate it !!

[@elishajoaquin218]

@Yusuf Nash No problem :D

[@crazyzombie99]

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)

[@mohammadalimatinvafa3245]

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

[@ellamadden208]

who's here from online school??

[@micah9988]

yeah

[@maxtrimmer1227]

Me

[@traxluh]

No talking in class

[@robbyjones9489]

We out here

[@user-rf3jo3be5v]

Me too from🇯🇵🇯🇵

[@bambam4567]

Too good! Straight to the point!

[@MediaBuster]

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

[@crawdad4823]

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

[@AmruMagdy]

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

[@TheMcardarelli]

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

[@eclipse369.]

cannot be used for diagnosis

[@B3bita1215]

Perfect animation and perfect explanation. Thanks for sharing :)

[@Kaitopia_]

Very good, thank you! I needed a short and simple explanation for a college project.

[@nittyjee]

Best explanation ever.

[@ashokkushwaha7366]

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

[@ShyaamHaridasTHEHERO]

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

[@sanashaikh8804]

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

[@Bjulle2]

Very good visualization! Gives a good insight of the process! :)

[@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.

[@ajshawn]

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

[@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.

[@moxandnunzaarttm9800]

Thanks for posting this, it helped a tonne with the exam that I just had XD

[@vitalodion]

This is the best biology video i have ever seen!!!you have more of those??

[@RomanticPopPunk]

Thank for the video! It answers a lot of questions I had at the moment

[@saracahill3783]

Great simple explanation thank you!

[@dcdean01]

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?

[@84mcarson]

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.

[@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.

[@p8chill]

DNALEARNINGCENTER IS SOOOOOOOOOOOOO HELPFUL. I LOVE IT!

[@mistakenmillenial6834]

Thank god for this video. Was lost but now i get it.

[@sai-ij8es]

simple and efficient explanation, thanks a lot!!!!!!!

[@Andrew-hr7yr]

thats some jiggly as fuck dna man

[@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.

[@thorn_princess]

~Gratitude and love from India

[@robcullen2]

best animation about PCR! thanks!

[@woodmonster16]

this is way better than my teacher's crappy notes - thanks!

[@animamundii]

This is the only video that explained clearly, how do the markers get cut to just the specific length, when the primer is applied only to one side of the strand. I didnt realise it takes three cycles to get only the desired cut.

[@PatrickStaight]

Do the primer sequences ever both bind to the same single strand of the original DNA?

[@camilserapian7675]

Where will you get your primers ?

[@DanitoDaDorito]

what happens to the original DNA strand that contains genetic sequences that are no longer needed? do they remove it through gel electrophoresis?

[@simonekirkland6947]

Thank you so much!

[@unnatikumar9074]

that was really helpful!

[@malmizar]

is blue polymerase? and gold is primer??

[@bitiminicik]

I wonder how the temperature can go up and down so fast.

[@johnnyfrisco5354]

Brilliant explanation and animation... just gone out the other ear though

[@isam1335]

what is the primer in the PCR?

[@mr.mustache4743]

Wow amazing information!

[@crazyzombie99]

very nice explanation

[@bunnyotaku777]

this might be an ignorant question but... does this mean cloning is possible using this concept?? i mean like building off from this concept

[@MediaBuster]

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

[@seanpadraigobrien1260]

He'd be very unhappy how his test is being used now.

[@MediaBuster]

@@seanpadraigobrien1260 Not at all.. He rejected it being used for viral loads and spoke out against it. It was NOT invented to be used to diagnose disease.

[@seanpadraigobrien1260]

@@MediaBuster that's why I said he'd be very unhappy that his test is used for viruses

[@MediaBuster]

@@seanpadraigobrien1260 Sorry I misread it. My bad.

[@seanpadraigobrien1260]

@@MediaBuster No worries. It's quiet common to assume people might not be aware of karys intent and purpose of the PCR test and I've no science background, just been reading up on this legend of a man since this madness started this year. It's pretty ironic that he passed away last August and then all this kicked off. Like they knew he would be one of the main outspoken people against the whole thing.

[@cloutfisher7714]

Her voice sounds like the voice that self-checkout registers use at grocery stores

[@joshjohnson1033]

great video!

[@fastteddyb]

So am I right in thinking this technology is specifically designed to take something that is in minuscule amounts and almost impossible to detect and magnify it billions of times? Wow if that's true.

[@zanderez]

Shouldn't it be short RNA strands, not DNA strands?

[@K3v1nPr0]

THANK YOU!!!!

[@FilipiusApo]

amazing

[@dee7793]

How are the strands prevented from re-forming Hydrogen bond when the temperature is lowered to 55 degrees?

[@archonsouthpaw8690]

I know this is an old question, but in case anyone else reads this and needs help: Basically, they're not. It's all kinda going on at random in the tube. Some copies of the DNA may reform the duplex, and some will attach to the primers. Those that have the primers won't remake the duplex because the primers are in the way. Those that do remake the duplex won't attach the primers in that cycle and therefore won't copy because the polymerase has no primers to get it attached to the DNA. But in that case other DNA molecules will get copied, and then maybe this particular molecule (the one that reformed the duplex) will get to make copies in the next cycle because maybe the primers will attach next time.

[@foldedpapermoon5640]

ANY PRIMERS??

[@boxa888]

@watashiwaka19501 i know that there are viral cutters and mending chemicals that chop up dna and push it together, because thats the same mechanisms that viruses use to hijack your cells, but from this process i think it has to have more than one PCR step to target more precise gene sequences. great video but i think some more important parts are not shown, yea there is got to be more to this, i wonder what the primers and polymerase steps are called.

[@Aleatha]

Had a lot of fun with the comments, ( I'm bilingual too ) - a very nice distraction from learning for biology und biologie =) Anyways, a very good video that helped me a bit more to understand the PCR, even if it was not very detailed. Thank you for that!

[@MrBasantarai]

cannot download

[@irunonwindows]

omg this is soo cool!

[@anoodalassaf7130]

perfect !!

[@vincetheworldly537]

What prevents the single stranded DNA from sticking to each other when the Temperature was lowered for the attachment of the primers?

[@jeromeyue96]

They are denatured. Meaning that they have "lost" their shape and structure. Scientists are more concerned when the primers attach wrongly when the temp. is set too low. I did PCR and Post PCR stuff. PCR is seriously hard. There are so many ways you can screw the experiment up.

[@ragulmrnr]

They use excess DNA primer to lower the chance of that from happening, although it happens.

[@shodanxx]

How do you control where the primer will attach ?

[@CullenSVens]

+shodanxx By designing primers that are specific to a sequence within your stretch of the gene-of-interest. The longer the primer you design from your sequence, generally speaking, the more specific it will be to that sequence.

[@ca0lu]

now I understand what's going on in PCR

[@infotainment365]

simple and great

[@Raphi]

How do you get the primers to attach at the desired location?

[@henrikslab]

you need to know exactly where you want to start with synthesis... the sequences can be checked in databases (e.g. NCBI genome browser). According to your target region you order the reverse complementary sequence of the forward primer and the same sequence for the reverse primer. Long story short: a primer needs to have the complementary sequence (A binds to T and C binds to G) and when this is accurate, a certain temperature helps to anneal to the target DNA.

[@drahmedeidify]

thanks so much

[@EmidioPaniago]

MUITO BOM O VÍDEO

[@vladimirhorowitz]

@ForYeensSake Wow that's a new one. I probably have only heard that one about 4389747239374893 times since I started using the Internet.

[@boxa888]

ok how do you make the primers, do you add A T G C in a sequenced mix in test tubes and heat treat to cause them to bind into the gene sequence that you want? how do we know that the right genes are being targeted, because at some point the A T G C repeat at different parts along the DNA strand, this process cannot directly find the genes, im guessing its multiple processes after the target strand is found so you take the smaller part and then subdived off of that to get precise gene pieces.

[@jeremiasaari9600]

Primers are usually about 18-22 bp in length. This so they're long enough to accurately find the right place where to bind, but also short enough to anneal properly.

[@doczak69]

What is the clinical use of PCR?

[@theunraveler]

+doczak69 well, for infectious disease if u are interested to find if certain viruses, bacterias, fungi, protozoa are in a biological sample, PCR can amplify the DNA signature of the suspected pathogen.

[@realesha]

ayo it copies from 3 prime to 5 prime

[@aldoilnegro]

GREAT!

[@torikdib2070]

yeah same here studieng for the hsc biotechnology section

[@dridri906]

I love PCR BIATCH

[@JamesStiling1985]

PCR is so cool

[@theov3rmind]

Abathur spin strands

[@Basiriku]

Not as informative as could be, but really beautiful

[@HUGOVANTA]

just great

[@CTVAK69]

Those jiggles tho 😂

[@user-vq2yv4ue2s]

يعني هسة دي أن اي مالتي يشبه هذ

[@charlespeter9914]

With this clip, u can go to the lab with some ideas. Thanks DNALearing center

[@TKswitch]

It happens to the best of us.

[@alonir101]

Great video

[@emma-zl8tu]

bio class be like uh uh sorry if someone from my school sees this

[@memo621ciwan]

Gooood

[@ratboys8689]

ha this is getting done to my dna sample right now

[@Sarakathir]

well and good....

[@Thepiccolopower]

Science is awesome

[@atishyadav1271]

Kuch samajh nhi aa raha

[@asifashamim1973]

good

[@irekooo20]

i love you ..

[@theogdagny]

Deanna Troi talks PCR.

[@itsquran]

سبحان الله وبحمده سبحان الله العظيم

[@allencat1]

Sums it up in a couple a minutes...

[@lishy20121]

Great clip! My bio prof should retire already :S

[@Angericful]

cool!

[@mallakatani3918]

Yes !

[@theogdagny]

The narrator sounds like Marina Sirtis.