Thermal equivalence of DNA duplexes without calculation of melting temperature

The common key to nearly all processes involving DNA is the hybridization and melting of the double helix: from transmission of genetic information and RNA transcription, to polymerase chain reaction and DNA microarray analysis, DNA mechanical nanodevices and DNA computing. Selecting DNA sequences with similar melting temperatures is essential for many applications in biotechnology. We show that instead of calculating these temperatures, a single parameter can be derived from a statistical-mechanics model that conveniently represents the thermodynamic equivalence of DNA sequences. This parameter is shown to order experimental melting temperatures correctly, is much more readily obtained than the melting temperature, and is easier to handle than the numerous parameters of empirical regression models.