Multiplex STR Analysis Using Six-Color Fluorescent Detection
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Solution Overview
Problem
Current STR analysis methods face limitations in multiplex density and locus size range, preventing the simultaneous analysis of more than 18 loci with high discrimination power, especially in degraded DNA samples and international database compatibility.
Innovation Solution
The method involves using six or more fluorescent labels in PCR to amplify multiple STR loci, allowing for higher multiplex density and locus size range, enabling the simultaneous analysis of up to 35 or more loci with improved confidence in forensic and kinship analyses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional PCR methods are used for STR analysis, then the analysis can be performed with standard equipment and protocols, but the multiplex density is limited to less than 3.20 and only up to 18 loci can be analyzed simultaneously
Solution Approach 1:
The patent transitions from conventional single-dimension fluorescence detection to multi-dimensional detection by employing six or more fluorescent dyes with distinct emission spectra. This dimensional expansion in the spectral domain enables simultaneous analysis of 35 or more STR loci, fundamentally increasing multiplex density beyond the conventional limit of 18 loci while maintaining compatibility with standard PCR equipment
Solution Approach 2:
The invention changes the parameter of fluorescence detection by using six or more fluorescent dyes instead of the traditional limited palette. Each dye is assigned to specific primer pairs for different STR loci, allowing high-resolution spectral discrimination. This parameter change in the detection system enables the analysis of 35+ loci simultaneously with multiplex density of 3.20 or greater
2Reliability
If more STR loci are analyzed simultaneously to improve discrimination power, then the confidence in forensic and kinship analyses increases, but the complexity of the multiplex assay and difficulty of optimization increase
Solution Approach 1:
The patent segments the complex task of analyzing 35+ STR loci by assigning specific fluorescent dyes to specific primer pairs and STR loci groups. This segmentation allows systematic organization of the multiplex assay, where each dye-channel combination is optimized independently, reducing the overall optimization complexity while maintaining high discrimination power through the analysis of numerous loci
3Quantity of substance
If the number of fluorescent dyes is increased to six or more, then the multiplex density increases to 3.20 or greater enabling analysis of 35+ loci, but the cost of reagents and complexity of detection increase
Solution Approach 1:
The patent employs six or more fluorescent dyes that can be detected by a single laser-induced fluorescence detection system. This multi-functional approach allows one detection instrument to handle multiple wavelengths and distinguish emissions from different dyes, enabling analysis of 35+ loci without requiring multiple specialized instruments, thereby maintaining ease of implementation despite increased multiplex density
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases the likelihood of successful amplification in degraded DNA samples, enhances the confidence in forensic and kinship analyses, and facilitates international STR standardization by allowing more loci to be analyzed simultaneously, reducing adventitious matches and improving database compatibility.
Implementation Method 1
detecting the nucleic acid products by laser induced fluorescence
Data Source
AI summary
Provided are methods for multiplex polymerase chain reaction (PCR) amplification of short tandem repeat (STR) loci that can be used to rapidly generate a highly specific STR profile from target nucleic acids. The resulting STR profiles are useful for human identification purposes in law enforcement, homeland security, military, intelligence, and paternity testing applications.