>CSI rolls in >Oh look, a cigarette. >Get Dave to run

>>7712949
I take it you don't know much about how PCR works. Is this correct?

You need enough DNA to be able to see it on a gel. That's usually exponentially more than you'd find laying around.

>>7712949
well, with one egg I can fry it
with 3 I can fry, hardboil, and poach

>>7712956
This is quite possibly the single shittiest analogy I have ever seen.

>>7712949
You can see one chocolate bar from ten meters away, you can see 1*2^35 chocolate bars from space. (A typical degree of amplification)

>>7712953
I understand how it works but not why it is required. Do you understand, is this correct?

>>7712954
Thank you for answering the question but I don't think you understand what 'exponentially' means.
You are essentially saying: "That's usually in a manner of rapid growth more than you'd find laying around." No?

>>7712954
Gel electrophoresis? Is there any alternative methods of 'profiling' the DNA or do I have the understanding wrong?

>>7712976
Why do I wan't to see them? I can the v. small about of extracted DNA not be put directly through a sequencer?

>>7712982
Okay, you get your sample, do PCR without amplifying, and you can't see shit on the gel. Does it make sense now? They don't sequence the genome lol. PCR has nothing to do with sequencing

>>7712989
lol my bad. Back to reading I go.

>>7712982
>Gel electrophoresis? Is there any alternative methods of 'profiling' the DNA or do I have the understanding wrong?

Yes, but PCR is quick and cheap. Sequencing is time-consuming and more expensive.

>>7712949
Try looking at 1 chocolate bar except the chocolate bar is 30nm wide. Its easier to make 100000 chocolate bars and then spread it evenly over a sheet organised by size of the pieces(electrophoresis)

>>7712987
no

>>7712987
This is bait right? a piece of DNA cant just be strung through a machine that spits out the order of base pairs, its really really fuckin small.

>>7712949
>Why does DNA have to be amplified for the suspect to be caught?

You could amplify it to carry out further tests. PCR alone is not enough to convict someone.

>>7712982
>You are essentially saying: "That's usually in a manner of rapid growth more than you'd find laying around." No?
No. Does 2^3 grow?

>>7712959
was trying to match how shitty OP's question was

>>7712989
But you do need PCR for sequencing, at least if you want to sequence the DNA in your lifetime.

That's not the interesting question. The interesting question would be how the hell do they alter peoples' dna to the point of changing their blood type and physical features. There was a study on these occurrences. And its mind altering nonetheless.

>>7713477
I heard they did it to a whole bunch of Jewish people. And some other minority groupings. Its crazy and to a point makes everything seem so fictional.

I like how arrogant the OP was until he realized he was an idiot.

Delicious.

File: nanopore_x616[1].jpg (84KB, 616x652px) Image search: [Google]

84KB, 616x652px

>>7713059
>>a piece of DNA cant just be strung through a machine that spits out the order of base pairs
But anon, that's exactly how nanopore sequencing works.
https://en.wikipedia.org/wiki/Nanopore_sequencing

You can also, read out the base pairs using an STM
http://www.nature.com/nnano/journal/v4/n8/full/nnano.2009.155.html


These technologies aren't up to par to do the CSI sort of stuff though.

>>7713609
Sure you can sequence a single strand, but think how expensive that is.

It's way cheaper to PCR and Sanger sequence.

Also when you're doing sequencing for a police investigation you need to have zero error. Easy way to do that is to go into analysis with a shit load of DNA.

>>7713646
For now.

>>7713646
>>7713646
>>7713646
the answer is statistics. Single molecule techniques are bad because of reading error and contamination.

Better to amplify and get many copies to reduce copy bias and read error.

>>7713609
Wow, that is pretty impresive. Have you got the paper or at least the link to it? I would like to read more about it. (And know how much would cost that).

Ty,m8.

>>7714234
http://www.nature.com/nbt/journal/v26/n10/full/nbt.1495.html

here's a random paper I found that talks about it

>>7712949
There's not enough DNA collected on the scene for them to conduct a full analysis.

Analysis procedures generally destroy the DNA

>>7714242
Thank you.

"Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of 'third generation' instruments that will sequence a diploid mammalian genome for ~$1,000 in ~24 h."

It would be cheaper than I thought. A lot cheaper.

>>7714264
There are companies that will sequence your PCR product for fairly cheap. That being said, most of them do their business with college labs.

Qiagen is a good one. They did some pea plant PCR sequencing for a class I was in last semester. You also get data on how conclusive the readings for each individual base pair is which was pretty sweet.