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lalyil
02-21-2013, 02:46 PM
Hello everyone,

My story is set in a post-apocalyptic world (however, decades after the actual "apocalypse"). I was wondering if a survivor of such apocalypse who worked in a police DNA lab prior to it, would be able to fix up and continue working in such a lab. I don't know what would be needed to keep it working and if one person alone can do it. What are the chances anyone knows? :)

areteus
02-21-2013, 03:12 PM
Depends on the situation... one thing that all modern labs need is power and DNA labs need it to run centrifuges and PCR machines. Now, I have joked in the past when doing PCR that in theory you *could* perform PCR by having three water baths at three different temperatures (painstakingly maintained by using thermometers and some form of heater such as a gas heater or spirit burner) and someone sat there moving tubes from one to the other in sequence every 1-3 minutes for 4 hours but it is not going to be easy...

Then there is maintaining sterility and getting hold of supplies of things like polymerase enzymes and nucleotides...

You also need power to run electrophoresis agarose gels to analyse your DNA and presumably a database of DNA to compare it too...

Frankly I am not sure it is all that likely to achieve all of these. It might, however, depend on what procedures you were wanting done... in most forensic applications you need to at least do PCR in order to bulk up what are usually very small amounts of DNA so you can do more with it.

waylander
02-21-2013, 03:19 PM
Might well be a problem with high purity solvents and reagents such as buffer solutions.

lalyil
02-21-2013, 03:22 PM
Thank you for your reply.

They will have power, since it's a few decades after the apocalypse they already rebuilt a little bit of the modern society that was.
I'm just unsure where to get the other stuff lol if one wanted to get DNA of a drop of blood or hair, and then save it into a database (I don't need an existing database for what I'm writing, this is prior to DNA searches)

lalyil
02-21-2013, 03:27 PM
Thank you waylander. I wonder if one could use such compounds from before the apocalypse, keep them "working".
I guess it's a long shot and maybe I should drop the DNA storyline.

waylander
02-21-2013, 04:41 PM
Some of these reagents have a shelf-life, so decades on my instinctive answer would be no.

Unimportant
02-21-2013, 10:17 PM
It depends on what he's doing in the DNA lab. PCR? DNA laddering?

For extractions, once the handy-dandy kits are no longer available, he could go back to the ye-olde chlorophorm/phenol extraction method: those chemicals have a shelf life of pretty much forever, I think, as long as they're stored correctly. He can pour his own gels making his own base reagents which, again, have a long shelf life. But it really depends on what he's doing with the DNA. What kind of tests is he running?

Buffysquirrel
02-21-2013, 11:09 PM
There's a question for me around what is the lab achieving for the new society that's worth using the resources it'll consume.

quicklime
02-21-2013, 11:40 PM
Depends on the situation... one thing that all modern labs need is power and DNA labs need it to run centrifuges and PCR machines. Now, I have joked in the past when doing PCR that in theory you *could* perform PCR by having three water baths at three different temperatures (painstakingly maintained by using thermometers and some form of heater such as a gas heater or spirit burner) and someone sat there moving tubes from one to the other in sequence every 1-3 minutes for 4 hours but it is not going to be easy...

.


that's been done

(fuck, that makes me sound old)

DNA as a dried pellet, for example, would last for ages....but the other stuff would be a problem--polymerase enzymes for example, which elongate the daughter strands, would become unstable once the -80 freezers died, and even if they were safely frozen, I doubt they would work very well after decades.

that said, buffy perhaps asks the best question--other than "you want to do it" what is the payoff, and does that in any way outweigh the implausibilities you will have to try to address?? And why would the new society, fresh off an apocalypse and presumably vey short on resources of all kinds, have a lab like this? You could probably power a half-dozen homes worth of "general use lighting" for what you invest to keep your freezers running, electrophoresis equipment, etc for even a small lab.

melindamusil
02-22-2013, 01:22 AM
In my past life as a teacher, I had a student who did dna extraction as a science project. I've included a link below, and you can get more information by googling "dna science project". The project used basic household chemicals. However, it's a pretty rudimentary form of dna extraction. Might work but depends on what you want to analyze.
http://www.sciencebuddies.org/science-fair-projects/project_ideas/BioChem_p015.shtml

frimble3
02-22-2013, 02:30 AM
that said, buffy perhaps asks the best question--other than "you want to do it" what is the payoff, and does that in any way outweigh the implausibilities you will have to try to address?? And why would the new society, fresh off an apocalypse and presumably vey short on resources of all kinds, have a lab like this? You could probably power a half-dozen homes worth of "general use lighting" for what you invest to keep your freezers running, electrophoresis equipment, etc for even a small lab.
That's my question, too. Unless they're genetically identifying their greatly reduced population for some reason?
Because the number of crimes solved by DNA testing is fairly low, considering the resources it takes.

veinglory
02-22-2013, 02:34 AM
Some of the gels and other necessary consumables would not last long, and would be hellishly difficult to make from scratch single-handed.

Unimportant
02-22-2013, 03:46 AM
Some of the gels and other necessary consumables would not last long, and would be hellishly difficult to make from scratch single-handed.
Us oldies used to have to cast our own gels, yanno....

lalyil
02-22-2013, 04:19 AM
Wooha, thank you very much for all the discussion.

Well, first I'll answer the main question, without giving too much away since it's a public area of the forum, the only reason that DNA lab is needed is because of the paranoia of the leader. He turns to that method since he's desperate to find someone and he comes to hold a drop of blood and so he wants to begin DNA searches throughout the city..

I'm starting to think though if perhaps I should search for another way for him to go after that man/put that man on the run from said leader. Even if it's possible to operate such a lab in those conditions, I worry that it may sound too far fetched to the untrained reader lol

Unimportant
02-22-2013, 05:54 AM
I'll take too far-fetched for a hundred dollars.

If the only lead he's got is one drop of blood, and he wants to try and take samples from the entire population of thousands (or hundreds of thousands) of people in the city to do a DNA match -- hell, no, that isn't feasible unless you've got a top notch system with a lot of automation. And he'd need to either match restriction enzyme ladders or do PCR for a known gene variant. Both require enzymes that have a short shelf life even at -80 degrees Celcius. And if this guy's so good at evading that he's left behind no photos, no fingerprints, nothing but a single drop of blood, how the heck is anyone going to find him to take a second blood sample?

lalyil
02-22-2013, 05:58 AM
I'll take too far-fetched for a hundred dollars.

If the only lead he's got is one drop of blood, and he wants to try and take samples from the entire population of thousands (or hundreds of thousands) of people in the city to do a DNA match -- hell, no, that isn't feasible unless you've got a top notch system with a lot of automation. And he'd need to either match restriction enzyme ladders or do PCR for a known gene variant. Both require enzymes that have a short shelf life even at -80 degrees Celcius. And if this guy's so good at evading that he's left behind no photos, no fingerprints, nothing but a single drop of blood, how the heck is anyone going to find him to take a second blood sample?

The city isn't that big, it's made out of a few families of survivors and their descendants.. technology is also hard to come by due to the war that brought on the apocalypse.

But anyway, as already said, I'm probably scratching this storyline. Already got another cloudy idea instead that I'm trying to shape into something..

BDSEmpire
02-22-2013, 07:19 AM
By the way, it would be miraculous if any of the computers booted. Age and computers don't mix. Without those you're going to have a lot of trouble dealing with the data coming out of the machines, assuming they power up properly at all.

veinglory
02-22-2013, 07:25 AM
Us oldies used to have to cast our own gels, yanno....

Would you consider that less than extremely difficult in a world without ebay? Maybe if you had a step by step description and access to a good farm supply store....

Unimportant
02-22-2013, 12:03 PM
Ah, we used to make our gels out of clay and sticks. And we hauled water from the river to fill the tank. Uphill. And..... :D

lalyil
02-22-2013, 03:36 PM
lol!

Well, thanks a lot guys. You helped me make a hard decision lol electronics and such that people mentioned, I personally see the leader as the only one who has access to those and he puts a lot of manpower in order to fix them and keep them functioning. But a DNA lab is clearly too much so I'll still 'easier' stuff.

areteus
02-22-2013, 03:37 PM
Yes, the enzymes (or any biological reagant) would not be stable enough to last decades even with proper refridgeration and freezers. The old fashioned method of DNA extraction would work really well (it is more difficult than using a premade kit but with trial and error you could do it). If you have power you could in theory run a PCR using waterbaths instead of a cycler (or even have a cycler that still works) but the lack of enzymes may make it problematic... however, someone with the right knowledge base (likely not your forensics specialist, someone with a background in biotechnology) might be able to get a hold of the right bacterial genes to make the enzymes (you need a DNA strand for that gene from a volcanic vent surviving bacteria to transplant into ecoli for growing and then equipment like an FPLC to purify it) which will be difficult but possible with time and effort...

Of course the way these things usually work, there is nothing to stop the leader ordering this project done only to have his forensics specialist tell him all the reasons why it is a stupid idea...

lalyil
02-22-2013, 04:03 PM
Yes, the enzymes (or any biological reagant) would not be stable enough to last decades even with proper refridgeration and freezers. The old fashioned method of DNA extraction would work really well (it is more difficult than using a premade kit but with trial and error you could do it). If you have power you could in theory run a PCR using waterbaths instead of a cycler (or even have a cycler that still works) but the lack of enzymes may make it problematic... however, someone with the right knowledge base (likely not your forensics specialist, someone with a background in biotechnology) might be able to get a hold of the right bacterial genes to make the enzymes (you need a DNA strand for that gene from a volcanic vent surviving bacteria to transplant into ecoli for growing and then equipment like an FPLC to purify it) which will be difficult but possible with time and effort...

You summarized it excellently for me, with my English and complete lack of knowledge in the area this post made it clearest for me :) Thank you.



Of course the way these things usually work, there is nothing to stop the leader ordering this project done only to have his forensics specialist tell him all the reasons why it is a stupid idea...

Lol, yeah I think I'll give that a miss. It's a screenplay so don't need to go so deeply into it if I don't use it.

Trebor1415
02-23-2013, 12:19 AM
Just go lower tech. Make it so that the only bit of evidence is a single fingerprint instead. The dictator could try the very impractical plan of fingerprinting everyone and have people manually compare the prints. That could take years and have all sorts of technical and implementation problems, but in theory could be done.

He could also scale back to only taking fingerprints of people he is suspicious of for some reason. Heck, at that point he could compare them himself.

Now, there may be reasons a fingerprint won't work for your story, I don't know. From the plausibility angle at least it's more likely then DNA though.

lalyil
02-23-2013, 04:03 AM
Just go lower tech. Make it so that the only bit of evidence is a single fingerprint instead. The dictator could try the very impractical plan of fingerprinting everyone and have people manually compare the prints. That could take years and have all sorts of technical and implementation problems, but in theory could be done.

He could also scale back to only taking fingerprints of people he is suspicious of for some reason. Heck, at that point he could compare them himself.

Now, there may be reasons a fingerprint won't work for your story, I don't know. From the plausibility angle at least it's more likely then DNA though.

It was actually my plan B and I may very well go for it. I have plenty of reasons for it to actually work in my case ;) But thanks, good to see another one in favor of this plan hah

BDSEmpire
02-23-2013, 07:48 AM
Fingerprints are a great idea. You can use a puff of graphite and something sticky to pull a latent print off an object and put it on some paper. All of those things will be around for decades and centuries after some great catastrophe. Heh, the carbon in graphite will outlive all of us.

You need a good strong magnifying glass and a copy of the Fingerprinting merit badge manual (http://www.onin.com/fp/fpmeritbdg.html) from the Boy Scouts and you're well on your way to being able to identify the dirty scoundrel who has been eating your delicious salad in the work fridge!

Then again, to the untrained examiner, two fingerprints may match when they were left by different people altogether. Depending on how twisty your plot is, this is an excellent way to misdirect the anger of your fearful leader onto someone unconnected with the real conspiracy.

quicklime
02-25-2013, 11:47 PM
lol!

Well, thanks a lot guys. You helped me make a hard decision lol electronics and such that people mentioned, I personally see the leader as the only one who has access to those and he puts a lot of manpower in order to fix them and keep them functioning. But a DNA lab is clearly too much so I'll still 'easier' stuff.


well, even skipping the issues of probability, does it sound in line with your MC? Hussein had access to thermocyclers, but for a dictator it was always easier to break a little girl's foot with a sledge, burn a father, etc. to get a confession than to wait around for something as nuanced as science....