Patent ID: 8265879

Claim:
A computer-implemented method of determining a melting temperature, Tm, of DNA, the method comprising: receiving a dataset representing a melt curve for a DNA sample, the dataset including a plurality of data points represented as a sequence of data values {(X 1 ,Y 1 ), (X 2 ,Y 2 ) . . . (X n−1 ,Y n−1 ), (X n ,Y n )}, where X represents a temperature (T) value and Y represents a fluorescence intensity value; determining, with a computer system comprising a processor, an analytical expression that fits the dataset, wherein the analytical expression is determined by: calculating an approximation of a curve that fits the dataset by applying a regression process to a double sigmoid function to determine parameters of the double sigmoid function, the double sigmoid function having the form: a + bx + c ( 1 + exp - d ⁡ ( x - e ) ) ⁢ ( 1 + exp - f ⁡ ( x - g ) ) , where a, b, c, d, e, f, and g are the parameters; determining a derivative curve by taking the derivative of the analytical expression with respect to X; determining a value X max corresponding to a maximum derivative (dY/dX) value of the derivative curve; and outputting the value X max , wherein the value X max represents a melting temperature, T m , of the DNA sample.