Reassociation of nucleic acids in solutions containing formamide

Abstract

The effect of formamide on the thermal stability of native and reassociated DNA-DNA duplexes and DNA-RNA hybrids has been reexamined. In contrast to McConaughy et al. (1) it was found that the Tm for native DNA of E. coli, calf and P. pallidum was reduced by 0.60°C per each 1% increase in formamide concentration. As measured by thermal stability there is no loss of specificity of the reassociation and hybridization in the formamide system under our conditions.