Seed Bulk Trait Purity Analysis Using ddPCR Pooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting the absence of a specific genetic modification (GM) in large seed lots are not sensitive enough, leading to potential contamination and yield losses, and current detection methods are time-consuming and resource-intensive.
Innovation Solution
A method using specific primers and probes for the presence and absence of GM, combined with digital droplet PCR (ddPCR) to quantify the ratio of GM presence and absence in large seed batches, allowing for rapid and reliable detection of contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If common detection methods are used to test for presence of GM, then detection capability is achieved, but sensitivity is not sufficient to identify absence in large seed batches
Solution Approach 1:
The detection method segments the large seed batch into individual DNA samples through pooling strategies, where DNA from multiple seeds is combined into pools for parallel testing. This segmentation enables sensitive detection of rare contaminants (0.03% level) by distributing the detection burden across multiple smaller units while maintaining the ability to analyze large quantities of seeds efficiently
Solution Approach 2:
The invention replaces traditional mechanical/phenotypic detection methods (spraying tests, germination assays) with molecular biology-based PCR detection. This substitution enables highly sensitive detection of GM presence/absence at the DNA level, achieving 0.03% detection sensitivity without requiring plant growth or phenotypic expression, thus solving the sensitivity limitation for large seed batches
2Measurement precision
If phenotypic testing methods are used for trait purity analysis, then detection capability is achieved, but time and resources are consumed for germination and spraying
Solution Approach 1:
The invention substitutes phenotypic testing (germination, spraying, visual scoring) with direct genotypic analysis using PCR. By detecting the presence or absence of transgenic DNA sequences directly in pooled seed samples, the method eliminates the need for plant growth and phenotypic expression, reducing testing time from weeks/months to hours while maintaining high detection precision for trait purity analysis
Solution Approach 2:
The method performs preliminary DNA extraction and pooling from seeds before any phenotypic testing would be required. By analyzing the genetic material directly in advance of plant growth, the invention obtains trait purity information without waiting for germination or phenotypic expression, thus eliminating the time delay inherent in traditional methods
3Measurement precision
If phenotypic testing is used for non-herbicide traits, then detection capability is achieved, but practical scoring in large volumes is not possible
Solution Approach 1:
The invention replaces manual phenotypic scoring with automated molecular detection. By using PCR to detect transgenic DNA sequences in pooled samples, the method enables high-throughput analysis of any trait with a known DNA marker, regardless of whether the trait has a visible phenotypic expression. This substitution transforms productivity from manual scoring limitations to automated DNA analysis capacity, enabling testing of thousands of samples simultaneously
Solution Approach 2:
The invention creates a universal detection platform that can analyze any transgenic trait through DNA detection, making the method applicable to all GM traits regardless of their phenotypic expression. The same PCR-based approach works for herbicide tolerance, insect resistance, and any other trait with a detectable DNA marker, eliminating the need for trait-specific phenotypic testing protocols and enabling standardized high-throughput analysis across diverse traits
4Measurement precision
If high sensitivity detection is implemented, then contamination detection capability is improved, but additional cost and workload are incurred
Solution Approach 1:
The invention merges two separate detection objectives (adventitious presence testing and trait purity analysis) into a single integrated PCR assay. By designing primers and probes that simultaneously detect both the presence of transgenic sequences and the absence of wild-type sequences in the same pooled sample, the method achieves high sensitivity contamination detection without requiring separate testing workflows, thus reducing overall complexity despite the enhanced detection capability
Solution Approach 2:
The detection system is designed with universal applicability to serve multiple regulatory and quality control functions simultaneously. The same assay platform and sample pool can be used for both AP testing (detecting unintended transgenic presence) and trait purity analysis (detecting unintended wild-type presence), eliminating the need for separate complex testing protocols and reducing the cumulative workload and cost burden
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
Enables high-sensitivity detection of GM contamination as low as 0.03% in large seed lots, reducing resource consumption and enabling efficient quality management with dual-purpose AP and trait purity analysis.
Implementation Method 1
performing an amplification reaction using said first and second set of primers and probes on the pool of nucleic acid molecules
Implementation Method 2
detecting the signals generated by the amplification reactions of said first and second set of primers and probes
Data Source
Figure 1
AI summary
The present invention relates to the detection of contamination with wild-type (WT) probes in large pools of probes, for example seed lots, using amplification (e.g. ddPCR) with primers and probe specific for the WT and primers and probe specific for a genetic modification (GM).