DNA Sequencing Using the RGB Image Sensor of a Consumer Digital Color Camera

Abstract A novel method for Sanger DNA sequencing, as part of a compact and inexpensive DNA sequencer, using the RGB image sensor of a digital color camera was developed. Since the RGB image sensor can only detect up to three colors (wavelength bands), while Sanger DNA sequencing is required to detect four or more colors in order to quantify fluorescence of four different fluorophores in a mixed state during capillary electrophoresis, it is difficult to perform Sanger DNA sequencing using an RGB image sensor. Moreover, due to the spectral response of an RGB image sensor, fluorescence of the four fluorophores is detected only on the red and green channels, that is, not on the blue channel. To address the above-described issues, a two-color electropherogram was obtained by capillary electrophoresis of a sequencing sample and reproduced by best local fittings of two-color single peaks of the four fluorophores in chronological order. The fitted single peaks of the four fluorophores respectively give fluorescence intensities of the four fluorophores. That is, the two-color electropherogram is converted to a four-fluorophore electropherogram. The proposed Sanger-DNA-sequencing method was applied to a model sequencing sample, and the DNA sequence of 69-144 bases of the sample was accurately determined. This result is the first successful quantification of four or more fluorophores in a mixed state by using an RGB image sensor.