Using ethanol as a preservation method for shotgun sequencing

[samd199]

Hi all,

Basically I am collecting fecal samples from all types of animals. Insects, fish, reptiles amphibians etc and ideally I would freeze all of these samples but ethanol would be way more practical as I will be in the Amazon. I was wondering if anyone knew about the efficacy of preserving DNA in ethanol for both amplicon sequencing (16S) and metagenomics (shotgun). Also, if the sample "dissolves" in ethanol (like a loose stool that disintegrates), can you simply evaporate the ethanol to isolate the DNA? Any info or a point to a paper or forum would be appreciated!

If not I will resort to freezing the samples in a -20 freezer and then shipping them on ice in what will likely be a 24hr trip back to the states.

[Ben3]

Hello samd199

I know I've worked with people in the past that stored fecal samples in ethanol. I don't recall what the concentration was and how long they were left in the ethanol, but I know it worked.

Also, the paper below describes testing out different methods for fecal storage and it says that ethanol worked for them.

https://journals.asm.org/doi/10.1128/mSystems.00021-16

I think there are some commercial options as well, but I haven't done any storage or sequencing of fecal samples so I couldn't recommend anything.

If you don't have the proper concentration of ethanol. This paper (below) mentions that they used a -20 freezer and it worked similar to storage in a -80 freezer.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953882/

Best of luck!

[samd199]

thank you Ben3 . I have seen these papers but I believe they are both for 16S. I wonder if they uphold for metagenomics. If no one knows, this would be a very interesting methods paper to do.
Thanks!