Genetic analyzer resolution increasing at DNA melting temperature determination

The genetic analyzers resolution necessity explanation at DNA melting temperature determination is discussed in the article. Digitizing error, noise and baseline drift are the main factor of DNA melting temperature measurement error. In order to reduce the influence of these factors on the melting temperature Tm measurement error, DNA melting curve signals upgraded model and its parameters optimization methods based on the sigmoidal function (SF) approximating method are offered. The displacement and linear and quadratic dependences of the baseline on the temperature are taken into account in the above formula. The melting curve can be directly approximated by using of the proposed method as the construction of the derivative melting curve is not required. The initial data of the melting curve of the two mRNA samples NAP-22 obtained on the nucleic acid analyzer, which is commercially available at the Institute for Analytical Instrumentation of Russian Academy of Sciences (IAI RAS). The detailed procedure for the SF optimized parameters approximations method receiving is provided. The values of the melting temperatures of two identical samples are calculated. The difference in melting temperatures of these samples equaled to 0.06 °C can be explained by the adjacent holder tubes temperature gradient. DNA melting temperature measurement accuracy can be taken as the main parameter, which limits the genetic analyzers resolution. The initial data of the melting curve and the SF application results are presented in graphical form. The possibility of full calculation automatization to determine the DNA melting temperature is shown. A high resolution genetic analyzer at a certain temperature the DNA melting is shown.