Spectral calibration of fluorescent polynucleotide separation apparatus
View Patent ↗The invention relates to methods, compositions, and systems for calibrating a fluorescent polynucleotide separation apparatus. One aspect of the invention is multiple color calibration standards and their use. A multiple color calibration standard is a mixture of at least two polynucleotides of different length, wherein each of the polynucleotides is labeled with a spectrally distinct fluorescent dye. Another aspect of the invention is to produce total emission temporal profiles of multiple color calibration standards for use in calibrating fluorescent polynucleotide separation apparatus. The peaks corresponding to the fluorescently labeled polynucleotides in the total emission temporal profile may be detected using a peak detector that is driven by changes in the slopes of the total emission temporal profile. Calibration of fluorescent polynucleotide separation apparatus, with various embodiments of the methods of the invention, includes the step of identification of the labeled polynucleotides of the multiple color calibration standards. The process of spectral calibration of a fluorescent polynucleotide separation apparatus using a multiple color calibration standard may include the step of the estimating (extracting) of the dyes' reference spectra, using information from the peak detection process performed on the total emission temporal profile. Other aspects of the invention include systems for separating and detecting fluorescently labeled polynucleotides, wherein the system is designed for spectral calibration in accordance with the subject calibration methods employing multiple color calibration standards. Another aspect of the invention is methods and compositions for detecting the flow of electrical current through a separation channel of a fluorescent polynucleotide separation apparatus. These methods and compositions employ monitoring dyes. Monitoring dyes are fluorescent dyes that are spectrally distinct from the dye on the polynucleotide intended to convey genetic information, e.g., fluorescent polynucleotide sequencing reaction products.
1. A calibration standard for a fluorescent polynucleotide separation apparatus, the standard comprising: at least four polynucleotides each having a different known length and each being labeled with a different fluorescent dye having a distinctive spectral profile having a peak, wherein the lengths of the at least four polynucleotides differ from one another such that, upon electrophoretic separation, the peak of the spectral profile of any one of the dyes does not significantly overlap the peak of the spectral profile of any of the other dyes.
2. The calibration standard of claim 1 , wherein the fluorescent dye labeled at least four polynucleotides in the standard are separated by at least 10 bases in length.
3. The calibration standard of claim 1 , wherein the length of each of the at least four polynucleotides is in the range of from about 10 to about 1500 bases.
4. The calibration standard of claim 1 , wherein the length of each of the at least four polynucleotides is in the range of from about 10 to about 1000 bases.
5. The calibration standard of claim 1 , wherein the length of each of the at least four polynucleotides is in the range of from about 20 to about 500 bases.