Hair sample storage in room temperature?

[Futuregenetics]

Hello guys, lets say that I store hair in a paper envelope at room temperature. What would the definition of room temperature be? Also, which other considerations should I take? Should the hair sample for example be stored in a dark and dry place. I hope that you guys had a great weekend.:)

[StringJunky]

20^oC . This is 'standard' temperature.

[CharonY]

18 hours ago, StringJunky said:

20^oC . This is 'standard' temperature.

In lab protocols it typically refers to a temp range of 20-25.

[StringJunky]

1 hour ago, CharonY said:

In lab protocols it typically refers to a temp range of 20-25.

STP in my school days was 20C and 760mmHg. It turns out to be the NIST values and they call it NTP.

https://www.1728.org/stpcalc.htm

 
 

[CharonY]

1 hour ago, StringJunky said:

STP in my school days was 20C and 760mmHg. It turns out to be the NIST values and they call it NTP.

https://www.1728.org/stpcalc.htm

 
 

Typically RT is not used in the same way as STP is used. RT defines a broader range of temperatures and can vary on the application. Standard lab work generally refers to the mentioned 20-25 C.  In the pharmaceutical industry the range can be down to 15 C or between 20-25, depending on standards. Similar norms are used for regular storage of chemicals or other goods, for example.

[StringJunky]

3 minutes ago, CharonY said:

Typically RT is not used in the same way as STP is used. RT defines a broader range of temperatures and can vary on the application. Standard lab work generally refers to the mentioned 20-25 C.  In the pharmaceutical industry the range can be down to 15 C or between 20-25, depending on standards. Similar norms are used for regular storage of chemicals or other goods, for example.

Right.

[mistermack]

While I would agree with 20 deg as a reasonable substitute for room temperature, I don't see the attraction, if you are hoping to preserve dna.

From reading a few of the links, it would seem that dna degenerates like most food items, in that any cooling is better than room temperature, a fridge would be good, and a freezer would be very good. Bacteria are responsible for much of the degradation of dna.

I would put it in a tiny quantity of distilled water, and put it in a decent freezer at minus 20. If the dna of the ice man survived 5,500 years, and the dna of the meat in his stomach survived being cooked, eaten, and frozen all those years, then your hair samples should last well enough to be tested in five years time. 

I did try to search the internal temperatures of glaciers, but couldn't get an answer. I think the Ice Man glacier was at about 10,000 feet, I very much doubt if the average temperature was lower than minus 20. Probably a fair bit higher.

[CharonY]

On 10/15/2018 at 4:20 PM, mistermack said:

the dna of the ice man survived 5,500 years,

You'll have to know that the DNA was mostly degraded in tissue samples and there was just enough stuff there (or more precisely, DNA quality was low)  to allow the amplification of certain markers from initial isolates (or gut contents). It was not trivial to get sufficient high-quality material together to do decent sequencing. As a general rule in plaeogenetics, one starts of with grams of ground bone material to get out sufficient DNA as compared to the minuscule amount of fresh preparations.

Of course, if only sufficient material for PCR is needed, keeping it dry and cool would be sufficient. Freezing is a possibility, but I would not add water. During the time needed for freezing and thawing you will have more degradation in an aqueous environment. For PCR probably not a big issue, but overall not helping.

If you want to use a buffer, a higher pH solution with EDTA in DNAse free water would be a way.

Edited October 17, 2018 by CharonY

[Futuregenetics]

If i store hair in a paper envelope at room temperatur, how should the humiditity be in the room? For Insurance, how dry should it be in the room? Thanks for replies.

[CharonY]

As dry as possible. It is easier just to desiccate a small volume (using air tight boxes with plenty of dry packs or better,  a proper desiccator). Not letting the temp go too high is also important.

[mistermack]

It might be worth researching some murder cases that were solved using dna, and finding out how the samples were stored and how long they kept for. But you have to bear in mind that police laboratories might have the funds to do a far more intense test than what you can buy yourself. 

I'm beginning to wonder why futuregenetics wants to know about samples kept at room temperature. If you wanted to keep samples for later, it's obvious that freezing is the way to go. But if you have samples from years ago that have been kept at room temperature, and are wondering if they can still be tested, then I guess there's only one sure way to find out. 

But old police cases might give you a clue. Nowadays, samples are carefully kept in the best known conditions. Years ago, they were not. But old cases HAVE been re-opened and solved using poorly stored dna. So they might provide the answer.

[CharonY]

6 minutes ago, mistermack said:

But old police cases might give you a clue. Nowadays, samples are carefully kept in the best known conditions. Years ago, they were not. But old cases HAVE been re-opened and solved using poorly stored dna. So they might provide the answer.

Actually that is typically not the case and I suspect that this is precisely where OP got the info from. Most evidence are stored in large storage halls, and if they have enough funds they are climate controlled. Few actually have the funds to get or maintain freezers for storage. And sometimes freezing is not very compatible with the way the samples were acquired. Folks I know were involved in a study looking at DNA stability under standard storage conditions (e.g. climate controlled RT in sealed bags within large boxes) mostly to ensure that the evidence would still hold up for forensics after years, since the samples are routinely stored that way. 

Also most forensics labs are underfunded and do not have shiny new toys. Many samples never get tested or are part of a huge backlog. If you walk into some of those you are really going to miss your college lab.

[Futuregenetics]

21 hours ago, mistermack said:

It might be worth researching some murder cases that were solved using dna, and finding out how the samples were stored and how long they kept for. But you have to bear in mind that police laboratories might have the funds to do a far more intense test than what you can buy yourself. 

I'm beginning to wonder why futuregenetics wants to know about samples kept at room temperature. If you wanted to keep samples for later, it's obvious that freezing is the way to go. But if you have samples from years ago that have been kept at room temperature, and are wondering if they can still be tested, then I guess there's only one sure way to find out. 

But old police cases might give you a clue. Nowadays, samples are carefully kept in the best known conditions. Years ago, they were not. But old cases HAVE been re-opened and solved using poorly stored dna. So they might provide the answer.

I already have om sample in the freezer.

[Futuregenetics]

What should the humidity be? When I store the sample in room temperature. 

[StringJunky]

1 hour ago, Futuregenetics said:

What should the humidity be? When I store the sample in room temperature. 

I would dessicate it and keep it in a hermetically-sealed glass container in the dark to keep uv off it.

[Futuregenetics]

On 7.12.2018 at 6:10 PM, StringJunky said:

I would dessicate it and keep it in a hermetically-sealed glass container in the dark to keep uv off it.

Thanks for reply, however, as I aleady have stored the hair in an envolope I do not want to do anything more with the sample itself. However, what I can do is to adjust the humidity in the room.

[StringJunky]

1 hour ago, Futuregenetics said:

Thanks for reply, however, as I aleady have stored the hair in an envolope I do not want to do anything more with the sample itself. However, what I can do is to adjust the humidity in the room.

Is the envelope archival quailty?

[Futuregenetics]

On 18.12.2018 at 11:01 PM, StringJunky said:

Is the envelope archival quailty?

I doubt, I purchased the envelope either at the gas station or at the grocery store. 

[Sensei]

On 14.10.2018 at 9:50 PM, Futuregenetics said:

Also, which other considerations should I take?

You should have hair sample together with root, if you're interested in preserving DNA..

 

[StringJunky]

5 hours ago, Futuregenetics said:

I doubt, I purchased the envelope either at the gas station or at the grocery store. 

I would research archival storage products. Most paper is acidic. https://www.preservationequipment.com/Catalogue/Archival-Storage/Envelopes/Archival-Envelopes-Perma-Dur

Edited December 26, 2018 by StringJunky

[Futuregenetics]

On 12/25/2018 at 9:46 PM, Sensei said:

You should have hair sample together with root, if you're interested in preserving DNA..

 

I have stored some of them with root, but most of them were not stored with root. I guess that I should have stored all of them with root, since I am interested in presevering DNA as good as possible. 

On 12/26/2018 at 3:03 AM, StringJunky said:

I would research archival storage products. Most paper is acidic. https://www.preservationequipment.com/Catalogue/Archival-Storage/Envelopes/Archival-Envelopes-Perma-Dur

Thank you for the tip. However, since the sample is already collected I cannot change the envelope that the storage is stored in. 

[Futuregenetics]

So I decided to store the sample in room temperature. However as the summer approaches the temperatur in the room where the hair sample is has increased. If I put an air conditioner in the room, how will that affect the hair sample? The hair sample is stored in an envelope. 

[Futuregenetics]

On 5/23/2019 at 6:57 PM, Futuregenetics said:

So I decided to store the sample in room temperature. However as the summer approaches the temperatur in the room where the hair sample is has increased. If I put an air conditioner in the room, how will that affect the hair sample? The hair sample is stored in an envelope. 

What do you guys think about this?