Dear all, A couple of months ago I sent an email reporting rather frustrating sequencing problems. It appears we have found the source: The UV light box for cutting bands! When we narrowed down the problem to the gel cutting stage we proceeded by sequencing directly from a purified PCR product (even though we often get unspecific bands). The sequences were mostly ok, of course this protocol was no good for cloning. During our further investigations we found out that someone changed the light bulb around the time we had the first problems. Although the bulb hasn't been replaced yet it appears that cutting bands from Ethidium bromide gels is more productive than a cheap cyber green stain that we have started using in February. We also keep the UV exposure to an absolute minimum! Anyway, thank you all for the many suggestions. And to the couple of people who reported similar problems: Go and check you UV light bulb! Best wishes, Birgit Birgit Meldal, PhD Division of Transfusion Medicine Department of Haematology University of Cambridge National Blood Service Center Long Road Cambridge CB2 2PT Tel: +44 (0) 1223 548049 E-mail: bhmm2@cam.ac.uk bhmm2@cam.ac.uk