If Your Work Is Dna related then this might help ....Amplification Success is dependent on preservation method.Storage in a DMSO/EDTA /TRIS/SALT SOLUTIONS most effective for preserving DNA

Blood samples can be preserved in a lysis buffer solution at room temperature. Extracting the buffy coat from mammal blood and preserving the white blood cells in lysis buffer is optimal for DNA samples. The SED buffer mentioned before is great for archival of DNA at room temperature and can be more easily transported. You can also use 95% ethanol for DNA sample preservation, especially fecal and tissue samples. If ethanol is used then for long term it should be stored frozen and you should be aware that the alcohol can evaporate over time. Silica is good for dried or desiccated tissues.

Thanks Lone for the information. If you are preparing the DET's solution by your own, I feel maintaining the PH is a difficult task and a change in the PH may affect the DNA concentration. How to solve this issue?

Thank you very much Robert for the detailed information. But people suggest that ethanol cannot be used for long term storage, I don't know the reason but How far it is true? Did you check in this regard with your samples?

Yes, you need to make sure the pH is adjusted with each titration before the salts are added. If you can not due that then the salts do not go into solution. As far as the long term,we mostly use lysis (blood) and SED (tissue) buffer solutions on the shelf and have samples from 20 years ago that still provide adequate DNA. The ethanol samples are maintained in a -80 C ultracold freezer and the level of ethanol is checked periodically. Those samples are fine too, but you need access to a large bank of freezers. Frozen samples from over 35 years are still providing ample DNA.

For storing fecal samples, my own research showed that within 30 days there was no difference between alocohol and RNAlater solution. But for the long term storing, the RNAlater is the best choice.

For fecal samples I used Queen's college buffer and for some samples I had to use silica beads. The samples with silica did not work at all, but I do know that other researchers have used them successfully on the same species. What types of samples are you interested in storing? Just all in general?

Thanks Stephanie. I want the information for fecal samples, tissues , feathers and blood samples. Can you elaborate Queen's college buffer ?

Sure - 20% DMSO, 100 mM Tris pH7.5, 0.25 EDTA, saturated with NaCL. The reference is: Amos W, Whitehead H, Ferrari MJ, et al. (1992) Restrictable DNA from sloughed cetacean skin; its potential for use in population analysis. Marine Mammal Science 8, 275-283.

In my work I extract DNA all the time from fecal and tissue samples preserved in RNA later, most of the time I need to store the samples for many months even years in environmental temperature and the samples worked perfectly. When I used Etanol 90% the DNA the samples worked, however you can't store them for long periods. The silica it works good for fecal samples. However, I still thinking RNA later it is the best because if you need to ship the samples or travel with them it is not going to be a problem, as alcohol and silica gel can be, because some countries have restricted the transportation of this materials.

Thanks Nelson.

Can we extract DNA from samples stored in RNA later solution, as it is good for RNA (literature suggests)? What about extracting DNA from samples stored in RNA later solution?

Yes!!! we are able to extract good RNA and DNA from this samples, even from samples collected 4 or 5 years ago.

I use silica for storing fecal samples. I think the solution you put fecal pellets depends on the environment you collected in and the species. People have also had success with storing them in ethanol, but that did not work for me.

Please see attached for two recent reviews addressing this matter. Most of preservatives mentioned in this thread were compared.

Article Human tissue preservation for disaster victim identification...

Thanks Vicki and Dennis.

It all depends upon the end purpose of the samples.....

Good discussio. Better than being concerned about DNA extraction is thinking about the potential difficulties to the amplification process the estorage of feacal samples in RNA later solution can bring. Have anyone experienced amplification problems?

Hi, I was just wondering whether you have determined the best method to store feather samples? Specifically for DNA extraction.

Hi, I share with you two research works comparing different collection methods for fecal samples in microbiome studies.

Hi, I also started to work with DNA extraction of large carnivores. From my experience DET buffer is very ok but the only trick is that need to be carefully how to prepare that and mostly need to be fresh. Do not keep the tubes with DET buffer in the sun or longer time if you do not sampling. And is better to extract DNA as fast as you can after sampling and than you can keep the rest from a long time at the room temperature. The alternative is ethanol 96% but in that case you must me carefully with the DNA extraction since ethanol is an inhibitor of PCR reaction....that it. I never use silica beads since those sample are smelly and with DET buffer is ok, I can easily work all day with those samples :) good luck! Iasmina