The relative separation efficiencies of highly concentrated, uncrosslinked or low-crosslinked polyacrylamide gels compared to conventional gels of moderate concentration and crosslinking.

Abstract

The joint report [1] has shown that the separation of heteroduplex DNA from homoduplex DNA can be achieved by uncrosslinked polyacrylamide gels or gels of a very low degree of crosslinking (0.15%) with N,N'-methylenebisacrylamide (Bis), while conventional polyacrylamide gels of 2-5% crosslinking with Bis are incapable of such a separation in the absence of added denaturing agents. This result raised the question whether in application to other separation problems the same superiority of uncrosslinked or low-crosslinked polyacrylamide existed. To test that question, Ferguson plots were determined for the members of a DNA ladder (50 to 1000 bp) in polyacrylamide with 0, 0.1, 0.2, 0.3, 0.5% C (Bis), and the separation efficiency function, S, was evaluated in comparison with that in conventional 2-5% C (Bis) gels. S was found to be lower, not higher, in gels of low crosslinking at the respective maximally effective gel concentrations. However, the range of gel concentrations in which gels of low or no crosslinking were effective extended over a range of at least 10% T, while conventionally crosslinked gels were most effective over a range of 3 to 1 units of %T.