Greetings: For whatever it is worth, we have had very good results with
the Costar Spin-X columns in the purification and subsequent ligation
of DNA fragments. We have made the mistake of using low melt agarose -
don't do it! We invariably got agarose in our preps and appropriately
low 32P-dCTP incorporation when used as for probes. As long as we've
used regular agarose, followed by 2 phenol, 2 phenol/clfm, and 2 clfm
extractions, we have been very happy with the results so far.
haviland at kids.wustl.edu