Spermine and Spermidine

1Plant Breeding Institute, ARC, SF-31600 Jokioinen, Finland; 2Department of Genetics, SF-00014 University of Helsinki, Helsinki, Finland In a recent article describing the effects of various reaction conditions, Blanchard et al. ~1~ ment ioned that spermine and spermidine at concentrations between 0.5 and 3 mM had no effect on PCR amplification ~2'3> with their sequence-specific primers. Because we have observed with arbitrary primers and other DNA templates the concentrat ion-dependent effects of spermine and spermidine either alone or together in PCR, we would like to report our experiences here. The present experiments were run in 1991 and may therefore carry outdated features. The observation that barley (Hordeum vulgare) DNA samples isolated by two different methods, that of Wienand and Feix ~4~ and the other of Wagner et al., ~s) yielded different results when used as PCR templates gave an impetus to the present study. We deduced that a component was carried along with DNA from the solutions used in the latter method, which keeps the nucleic acids precipitated in the early stages of the procedure with PEG in the presence of polyamines. It appeared that the polyamines, spermine and spermidine, either alone or