Signal processing method for determining base sequence of nucleic acid
First Claim
1. A method for determining the base sequence of a nucleic acid by obtaining digital signals corresponding to an autoradiograph of a resolved pattern including plural resolved rows consisting of four rows formed by resolving each of four groups of a mixture of base-specific nucleic acid fragments on a support medium labeled with a radioactive element that have migrated in a one-dimensional migration direction on the support medium and processing the digital signals thus obtained to determine the nucleic acid base sequence, wherein the digital signal processing method includes the steps of:
- (a) generating from said digital signals a waveform including peaks representative of base position in the resolving direction and the signal level for each resolved row;
(b) selecting a search-fiducial point, an interval adjacent to said search-fiducial point, and a signal level on the waveform;
(c) defining a plurality of domains within said interval;
(d) first determining a mean signal level value of the waveform signal levels in said domains and then selecting a threshold signal value based on the mean signal signal level value;
(e) searching the interval to locate a peak having a signal level greater than the threshold signal value and, if a peak is located, identifying a band corresponding to a nucleic acid base at the position of the peak, wherein the located peak is then selected to be the next search-fiducial point and steps (b)-(e) are repeated to identify all of said bands on the resolved rows;
or, if no peak is located, selecting a new search-fiducial point a predetermined distance from said original search-fiducial point; and
(f) determining the nucleic acid base sequence from the sequence of the bands identified in step (e).
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Abstract
A signal processing method for determining the base sequence of nucleic acids from data on an autoradiograph is provided. An autoradiograph including a plurality of resolved rows is formed by resolving a mixture of base-specific DNA fragments or base-specific RNA fragments that have been labeled with a radioactive element in a one-dimensional direction on a support medium. The method detects bands along each resolved row corresponding to the nucleic acid bases from digital signal data representing position and signal level for each row. The digital signal data corresponding to the autoradiograph may be photoelectrically detected as stimulated emission from the recording of the autoradiograph of the resolved rows on a phosphor sheet or as visible images from the recording by the autoradiograph of the resolved rows on a radiosensitive material.
26 Citations
11 Claims
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1. A method for determining the base sequence of a nucleic acid by obtaining digital signals corresponding to an autoradiograph of a resolved pattern including plural resolved rows consisting of four rows formed by resolving each of four groups of a mixture of base-specific nucleic acid fragments on a support medium labeled with a radioactive element that have migrated in a one-dimensional migration direction on the support medium and processing the digital signals thus obtained to determine the nucleic acid base sequence, wherein the digital signal processing method includes the steps of:
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(a) generating from said digital signals a waveform including peaks representative of base position in the resolving direction and the signal level for each resolved row; (b) selecting a search-fiducial point, an interval adjacent to said search-fiducial point, and a signal level on the waveform; (c) defining a plurality of domains within said interval; (d) first determining a mean signal level value of the waveform signal levels in said domains and then selecting a threshold signal value based on the mean signal signal level value; (e) searching the interval to locate a peak having a signal level greater than the threshold signal value and, if a peak is located, identifying a band corresponding to a nucleic acid base at the position of the peak, wherein the located peak is then selected to be the next search-fiducial point and steps (b)-(e) are repeated to identify all of said bands on the resolved rows;
or, if no peak is located, selecting a new search-fiducial point a predetermined distance from said original search-fiducial point; and(f) determining the nucleic acid base sequence from the sequence of the bands identified in step (e). - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A signal processing method for determining the base sequence of a nucleic acid by obtaining digital signals corresponding to an autoradiograph of a resolved pattern including plural resolved rows consisting of four rows formed by resolving each of four groups of a mixture of base-specific nucleic acid fragments on a support medium labeled with a radioactive element in a one-dimensional direction on the support medium and processing the digital signals thus obtained to determine the nucleic acid base sequence, wherein said digital signal processing method includes the steps of:
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(a) generating from said digital signals at least two adjacent waveforms representative of base position in the resolving direction and the signal level for each resolved row; (b) identifying the peaks on each of the waveforms; (c) selecting one peak on one of the waveforms; (d) searching a given domain on either side of the selected peak to determine the existence of a peak on an adjacent waveform having a center corresponding to the center of the selected peak; (e) repeating step (d) to search each adjacent waveform generated in step (a); (f) determining the existence or nonexistence of a band corresponding to a nucleic acid base based on the presence or absence, respectively, of a series of corresponding peaks located on adjacent waveforms in steps (d) and (e); and (g) repeating sequentially steps (c), (d), (e) and (f) until all of the bands on a resolved row have been detected. - View Dependent Claims (9, 10, 11)
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Specification