Daphnia DNA Preservation

[Zoops]

Hey Everyone I was wondering if anyone would be able to help me out. I am going to have access to a large number of Daphnia of varying species this summer and I was going to take subsamples and save them for a later date. I want to eventually be able to use them for genetic sequencing but I will not be able to extract any DNA from the Daphnia right away. I was going to initially store them in 70% ethanol and store them in the freezer, because when I worked in an RNA lab we store precipitated DNA in isopropanol and I think a buffer and then put them in a freezer. I then read online somewhere that storing them in ethanol could skew the results when they were used to run gels. So I was wondering if anyone had any idea of how I could store whole Daphnia until it came time for me to start extracting the DNA and sequencing. It will probably be anywhere from 1 to 2 years before I would actually be able to sequence them. Any advice would be helpful.

[Arete]

absolute ethanol (100%) is fine for most mtDNA, nuclear extraction and PCR - RNAlater is better http://www.invitrogen.com/site/us/en/home/brands/Product-Brand/rnalater.html, directly into a LN2 dewar is better again, especially if you want to do allozyme work

[CharonY]

Freezing the tissue long-term at -80 works for most applications. As you are not trying to revive them it should be fine for yours, too.

For very sensitive stuf Extracted samples are more susceptible to damage/modifications (goes for basically all biomolecules).

[Zoops]

Thank you both. If I do freeze them at -80 do I need them in anything such as an alcohol or another medium. Or just freeze the organism by itself. And I'm assuming the temperature is in celsius? Also for the ln2 dreary I was looking online and they only hold for what looks like up to about 2 1/2 months to 3. Is there anything that would store them longer. Also with the RNAlater can that sit at room temp or should it be in a freezer as well. Sorry for more questions.

[CharonY]

If you have access to a lyophilisator I would probably just freeze dry them. That saves time if you use a grinding protocol. There is no need for alcohol either way. Quick freezing using e.g. liquid nitrogen is helpful, though.

[Zoops]

Thank you for helping me out I now just need to get access to this sort of equipment.