Thanks to all of you for your responses! Please find below all the messages that I received. For the most part, people said that they have not experience problems shipping the dry pellet but some people expressed some concerns about the ability to resuspend overdried DNA after applying the speed-vacuum. Cheers, Margarita _____ We regularly ship dry DNA and it works very well. EtOH precipitation and vaccum or air dry. Ship the pellet as is and rehydrate to use. Hope this helps Eric Parent Pêches et Océans / Fisheries and Oceans Institut Maurice Lamontagne/ Maurice Lamontagne Institute 850 route de la mer Mont-Joli, Qc G5H 3Z4 Canada _____ Hi, The company we currently use asks us to ship DNA in alcohol, but I think I did post some dry DNA pellet a long time ago. Best, Maureen _____ I don't know whether that helps but I used RNA stable (Biomatrica: http://www.biomatrica.com/rnastable.php) to ship my RNA samples from Germany to the USA for  later microarray analyses - and it worked pretty well!  I know that Biomatrica also offer "DNAstable" which - as I guess - should work similarly for DNA samples... For my RNA preparations I needed to speed vac - I guess it should be the same with DNA... As far as I remember you can download a pdf from the Biomatrica homepage which describes the procedures which are needed for preparing your samples - just have a look there... Good luck! Best, Dörthe Dr. Dörthe Becker Institute of Zoophysiology University of Münster, Germany Hindenburgplatz 55 48143 Münster Germany _____ We have good experience with freeze-dried samples. We received quite some genomic DNA samples from collaborators that way, but also normally primers are shipped freeze dried. I do not know about shipping pellets, but can tell you that we in rare cases air-dry pellets even over the weekend (but they are of course dry after a few hours) and they dissolve fine after the 2 days. So if the shipping is not too long, drying them and sending them should work as well. I would not recommend to speedvac them completely dry. In my experience an overdried pellet dissolves only very hard and it's not perfect for the DNA, either. I would in any case try some mock samples first to see if it works for your amounts, pellet size, extraction method, shipping conditions, ... Good luck! Sabine -- PhD student Max-Planck-Institute for Chemical Ecology Department for Entomology Hans-Knoell-Str. 8 07745 Jena Germany _____ it is fine to just ship tubes with the dry DNA pellet directly after DNA extraction; however, it would be best to re-suspend the pellet first to check the quality of the DNA before you send it. If you do this, then you can simply allow an aliquot of the re-suspended DNA to dry out at room temperature or speed vac under a low heat. It is not always necessary to go to the trouble of re-precipitating and drying the pellet (which also runs the risk of you loosing some of your valuable DNA). Hope this helps, Will G-C _____ I've done this quite a bit and there's never been a problem. Drying with a speed-vac would be best but if you don’t have one, then just letting it evaporate would be fine too. Probably best to put a tissue or something loosely over the top. You could put it in an incubator or heat block to speed that evaporation along but don’t set it too warm, else it might affect (denature) the DNA - no more than 40 deg I reckon. Make sure it’s totally dry before you seal it up and send it. All the best, Niccy Niccy Aitken Research School of Biology The Australian National University Canberra, ACT 0200. Australia _____ You should not have problems sending dry DNA. I have even send DNA in solution through Fedex and the PCRs worked after been stored in the customs office for days! DNA is pretty stable, and when is dry you shouldn't expect much troubles. cheers sergio Dr. rer. nat. Sergio Vargas R. s.vargas@lrz.uni-muenchen.de sergio.vargasr@ecci.ucr.ac.cr _____ I've heard the DNA can be hard to rehydrate after speed vac drying (I haven't tried so i dont know) It's my understanding that lyophylizing is better - that's how primers get shipped If you have access to a lyophylizer, its pretty easy - just practice with some colored water before drying your samples so you dont end up sucking the samples out of the tubes. the key is to make sure the samples never thaw best diana Diana Wolf phone:(907)474-5538 Associate Professor fax:(907)474-7666 Institute of Arctic Biology Dept. of Biology and Wildlife 311 Irving I 902 N Koyukuk Drive University of Alaska Fairbanks Fairbanks, AK 99775-7000 _____ What is the size of the DNA which you need to send? If it's high molecular weight material and the downstream application is library construction or similar, it might not be a good idea to vacuum it. We've sent DNA samples in the past in TE on dry ice.  Hope that helps! Best wishes, Kaustubh Gokhale Postdoctoral Researcher, School of Life Sciences, Arizona State University, Tempe 85281, Az, USA kaustubh.gokhale@asu.edu Margarita Maria Lopez