Dear All Many thanks to all who responded and apologies if I did not get back to everyone (some mails bounced), but here is a summary of the soundbites I received from the community. Briefly, at least one very reputable lab had replaced EtOH with RNA later or similar non-branded product and the genetic material was/is fine for subsequent analysis. There were many other queries and suggestions, of which drying was a popular choice, especially for tissues such as fish fin clips. I think that the comments provide really interesting reading and thanks to everyone who responded. Certainly food for thought for future strategies. Please see below. Cheers and best Si Creer ¡§From my experience the RNAlater solutions are fantastic for both RNA and DNA preservation at RT and lower temperatures. Tissue tend to become "rubbery" or "hard" in ethanol. My yields and quality of DNA was also much higher compared to ethanol storage. Dry storage also worked acceptably.¡¨ ¡§What kinds of tissues are you trying to preserve and what are your downstream plans for them? DNA-based work only? Beware that because of its EDTA content and low pH, RNAlater will dissolve some mineralized tissues and may form crystals around small, soft-bodied specimens (I work on marine worms) or small tissue samples.¡¨ Invertebrate Systematics, 2013, 27, 81¡V86 http://dx.doi.org/10.1071/IS12067 DNA preservation: a test of commonly used preservatives for insects Corrie S. Moreau A,D, Brian D. Wray A, Jesse E. Czekanski-Moir A,C and Benjamin E. R. Rubin A,B ¡§Our preferred method of preserving the samples and DNA is air drying. Briefly, we take a small fin clip (this can be done non-lethally) and place between a small piece of filter paper to absorb the moisture. The samples are then put into a desiccator (or warm dry area) for 3-5 days or until completely dry. We have found that the key to preserving high quality DNA is to begin the drying process immediately after the tissue is removed from the fish. Once fully dry, the samples can be stored for years at room temperature. As a bonus, this is a highly space-efficient method, and we can store a large number of samples in a small area, no reagents required.¡¨ ¡§We also handle some ethanol-preserved tissue. When possible, we transfer ethanol samples to a dried state for long-term storage. This process involves blotting as much excess ethanol as possible with a lab wipe or blotter paper, overnight evaporation in a fume hood, and then ~3 days in a desiccator.¡¨ ¡§We have recently extracted DNA from samples that have been stored at room temp on our sample shelf for about 10 years, and got good microsatellite and SNP genotype data from them. In my experience, the majority of the DNA degradation takes place in the first few hours following: 1) removal of the fin clip from the fish, 2) thawing of frozen samples, or 3) death of the animal, as with carcass samples from stream surveys. Once the tissue has dried, enzymatic activity ceases, so the quicker you can get the sample dry, the better. Most of the data-poor samples that I deal with are from salmon carcasses, and there seems to be a strong negative correlation between data quality and amount of time the carcass has been decomposing on the stream bank!¡¨ ¡§I should mention that each tissue sample gets its own envelope, on which all the relevant sample info is written (and later entered into an electronic database). We use small coin envelopes that are about 9 x 5.5 cm. I buy "#1 coin brown" envelopes from envelopes.com in the US, but I'm sure there is a similar retailer in the UK. The blotter paper is Whatman 1 filter/blotter paper 46 x 57 cm, which we cut into ~2.5cm squares.¡¨ ¡§exchanging RNA later for ethanol is fine for fin clips¡¨ Simon Creer Senior Lecturer Molecular Ecology and Fisheries Genetics Laboratory School of Biological Sciences Environment Centre Wales Bangor University Gwynedd LL57 2UW Tel: +44(0)1248 382302 Fax: +44(0)1248 382569 web: http://mefgl.bangor.ac.uk/si.php Skype: spideycreer Twitter: @spideycreer Rhif Elusen Gofrestredig 1141565 - Registered Charity No. 1141565 Gall y neges e-bost hon, ac unrhyw atodiadau a anfonwyd gyda hi, gynnwys deunydd cyfrinachol ac wedi eu bwriadu i'w defnyddio'n unig gan y sawl y cawsant eu cyfeirio ato (atynt). Os ydych wedi derbyn y neges e-bost hon trwy gamgymeriad, rhowch wybod i'r anfonwr ar unwaith a dilewch y neges. Os na fwriadwyd anfon y neges atoch chi, rhaid i chi beidio a defnyddio, cadw neu ddatgelu unrhyw wybodaeth a gynhwysir ynddi. Mae unrhyw farn neu safbwynt yn eiddo i'r sawl a'i hanfonodd yn unig ac nid yw o anghenraid yn cynrychioli barn Prifysgol Bangor. Nid yw Prifysgol Bangor yn gwarantu bod y neges e-bost hon neu unrhyw atodiadau yn rhydd rhag firysau neu 100% yn ddiogel. Oni bai fod hyn wedi ei ddatgan yn uniongyrchol yn nhestun yr e-bost, nid bwriad y neges e-bost hon yw ffurfio contract rhwymol - mae rhestr o lofnodwyr awdurdodedig ar gael o Swyddfa Cyllid Prifysgol Bangor. This email and any attachments may contain confidential material and is solely for the use of the intended recipient(s). If you have received this email in error, please notify the sender immediately and delete this email. If you are not the intended recipient(s), you must not use, retain or disclose any information contained in this email. Any views or opinions are solely those of the sender and do not necessarily represent those of Bangor University. Bangor University does not guarantee that this email or any attachments are free from viruses or 100% secure. Unless expressly stated in the body of the text of the email, this email is not intended to form a binding contract - a list of authorised signatories is available from the Bangor University Finance Office. Simon Creer