A numerical optimization approach for color correction in forensic DNA genotyping

Recent advances in sequencing technology made short tandem repeats (STR) genotyping a leading tool in forensic DNA analysis. STR genotyping is performed using electrophoresis where DNA strands with different fluorescence labeling dyes are separated according to their length. Shorter strands arrive earlier at the detector where the attached dyes are excited by an induced laser. The resulting excitation is collected using a multichannel detector, with each channel tuned to detect the strength of a certain labeling dye, utilizing photomultiplier tubes or CCD devices. The spectrum overlap of the dyes causes a detector tuned to the wavelength of a specific dye to also detect with different sensitivity other dyes. In this work we propose a new numerical based algorithm for correcting cross talk resulting from such spectrum overlap. We discuss reasons earlier solutions to a similar problem can not be applied in the genotyping setting. We test our proposed algorithm and report preliminary results showing the success of the algorithm.