Dear Evoldir A few weeks ago I posted a query on Gel extraction kits. Thanks to all the replies, especially Robert Marra, Luiz Marquez, Rossana Giordano, Karen Osborn, Will Fairbrother, Violeta Munoz and Carla Hurt. I promised several people a summary of what I found, it follows right now, Yours Tom Gilbert For DNA fragments <10kb: QIAquick gel extraction kit - specifically one user found 80% recovery of a 1.5kb fragment and 60% of a 4kb fragment. Millipore Montage Gel Extraction Kit with Ultrafree-DA centrifugal filter was recommended Afurther reply indicated that a comparison of kits showed Zymoclean Gel DNA recovery kit was best, Zymo Research Cat #D4001, for DNA from 75kb-23kb There were a couple of more detailed replies that are also of interest: The enzyme Gelase was recommended. Specifically: I used to use Promega gel purification column kit but recently I've switched to using Gelase followed by ethanol/ammonium acetate purification. The protocol is very easy. You don't have to change tubes or mess with columns which is where much of the DNA loss occurs. I find that the yield is very good and usually very clean so long as the digestion is complete. I've tried it on DNA up to 2kb but I suspect it would work with any size. Modified protocol 1.)Melt the gel at 75 degrees 2.)Cool it to 45 and then add the enzyme 3.)Let the gel digest at 45 degrees overnight (shorten the time by adding more enzyme) 4.)Add 200ul 5M ammonium acetate and 800 ul absolute ethanol 5.)Centrifuge at high speed for 30 minutes 6.) Wash with 70% ethanol 7.) Evaporate the ethanol and rehydrate in water ............. And then some useful insights followed in this message: My experience is the lower percentage gel you can use the better the whole thing works. But I can't say I have found anything that I am all that happy with. I like the old school Crush n' Soak method (Maniatis) - it gives you about 50% recovery but the DNA is very clean. The kits are not that great. I feel like I have tried many and The Squeeze and Freeze (Biorad) is quick and easy. It sometimes gives you 70% but is dirty. you have to do a phenol chloroform precip afterwards. Make sure you cut the gel into little pieces. Invitrogen's kit was bad. I found the quiagen gel extraction kit better if the initial digestion is done longer than the recommended time with lots of mixing. Colleagues swear by electrophoresis based elution methods. There are combo UV boxes/horizontal electrophoresis apparatus were you cut cubes out of gels in front of the band, watch the DNA go in there, and suck it out with a pipet and extract. In grad school I cut out a cube with the band in it. Put the whole thing in a dialysis tube and chucked it back in the gel rig. That was efficient and you could see the ethidium stained DNA in a crease in the tubing but recovery was a hassle. It was hard getting DNA out in a small volume. Tom Gilbert