Differential Dissociation and Melting Curve Peak Detection

Abstract

Systems and methods are provided for processing a melting or dissociation curve of a DNA or other sample, for example, during PCR processing. In some embodiments, detection of the melting point and melting curve behavior can be enhanced by taking a derivative of the curve, and detecting peaks in the differential dissociation curve. In some embodiments, the derivative operation can comprise the use of edge-processing, or other detection algorithms. In some embodiments, the dissociation analysis can comprise removing low-frequency (or pedestal) components of the differential dissociation curve. In some embodiments, the differential dissociation curve can exhibit a smoothed or more regular appearance than the raw detected data.

1 . A method for determining the differential dissociation curve of at least one sample, comprising:
 interpolating emission measurement data of the at least one sample taken at uneven temperature intervals into data at equally-spaced temperature intervals; and   generating a differential dissociation curve by generating a derivative of the emission measurement data.   
     
     
         2 . The method of  claim 1 , further comprising detecting at least one peak in the differential dissociation curve. 
     
     
         3 . The method of  claim 1 , further comprising modifying the differential dissociation curve. 
     
     
         4 . The method of  claim 1 , further comprising generating a power spectrum of the interpolated emission measurement data. 
     
     
         5 . The method of  claim 1 , wherein the derivative comprises a first-order derivative. 
     
     
         6 . The method of  claim 1 , further comprising performing a frequency-domain transform on the interpolated emission measurement data. 
     
     
         7 . The method of  claim 1 , wherein the at least one sample comprises a plurality of samples each having associated emission measurement data. 
     
     
         8 . A system for determining the differential dissociation curve of at least one sample, comprising:
 an input unit for receiving emission data of at least one sample taken at uneven temperature intervals; and   a processor, communicating with the input unit, the processor being configured to
 interpolate the emission measurement data of the at least one sample taken at uneven temperature intervals into data at equally-spaced temperature intervals, and 
 generate a differential dissociation curve by generating a derivative of the emission measurement data. 
   
     
     
         9 . The system of  claim 8 , wherein the processor is further configured to detect at least one peak in the differential dissociation curve. 
     
     
         10 . The system of  claim 8 , wherein the processor is further configured to modify the differential dissociation curve. 
     
     
         11 . The system of  claim 10 , wherein the modifying comprises removing emission measurement data associated with peaks that fall below a peak detection threshold. 
     
     
         12 . A differential dissociation curve generated for at least one sample, the differential dissociation curve being generated by a method comprising:
 interpolating emission measurement data of the at least one sample taken at uneven temperature intervals into data at equally-spaced temperature intervals; and   generating a differential dissociation curve by generating a derivative of the emission measurement data.   
     
     
         13 . The differential dissociation curve of  claim 12 , wherein the method further comprises generating a power spectrum of the interpolated emission measurement data. 
     
     
         14 . The differential dissociation curve of  claim 13 , wherein generating a power spectrum comprises generating a normalized variance of the power spectrum and removing the emission measurement data of the at least one sample when the normalized variance of the power spectrum exceeds a predetermined threshold. 
     
     
         15 . A computer-readable medium, the computer-readable medium being readable to execute a method for determining the differential dissociation curve of at least one sample, the method comprising:
 interpolating emission measurement data of the at least one sample taken at uneven temperature intervals into data at equally-spaced temperature intervals; and   generating a differential dissociation curve by generating a derivative of the emission measurement data.   
     
     
         16 . The computer-readable medium of  claim 15 , wherein the method further comprises modifying the differential dissociation curve. 
     
     
         17 . The computer-readable medium of  claim 15 , wherein the method further comprises generating a power spectrum of the interpolated emission measurement data. 
     
     
         18 . The computer-readable medium of  claim 15 , wherein the derivative comprises a first-order derivative. 
     
     
         19 . The computer-readable medium of  claim 15 , wherein the method further comprises performing a frequency-domain transform on the interpolated emission measurement data. 
     
     
         20 . The computer-readable medium of  claim 15 , wherein the differential dissociation curve is generated in connection with a polymerase chain reaction process.