K-mer Frequency Analysis for Bacterial Detection Specificity

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Solution Overview

Problem

Nucleic acid-based detection systems for bacterial identification require prior information about target and off-target sequences, which is challenging due to bacterial genetic diversity, making it difficult to detect and differentiate between target organisms and background samples effectively.

Innovation Solution

The method involves establishing an out-group and in-group by extracting k-mers from sequences, with the biological signature identified as k-mers having an out-group frequency at or near zero, using a relative complement approach to differentiate between species of interest and background samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If prior information about target and off-target sequences is used for bacterial identification, then detection specificity is improved, but the method cannot effectively handle bacterial genetic diversity and complex background samples

Engineering Contradiction:
Improvedetection specificityVSAvoidability to handle bacterial diversity
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The method performs preliminary computational analysis by constructing k-mer frequency profiles from reference genomes before actual detection. This pre-computation creates a comprehensive database of species-specific and background k-mer patterns, enabling the system to adapt to bacterial diversity without requiring prior knowledge of specific target or off-target sequences in new samples.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention transforms the detection approach by changing from sequence-specific matching to k-mer frequency-based discrimination. By analyzing the distribution and frequency of k-mers rather than specific sequence matches, the method achieves both high specificity and broad adaptability across diverse bacterial genomes without requiring prior information about off-target sequences.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If comprehensive sequence information is analyzed to improve detection accuracy, then false positives and negatives are reduced, but computational complexity and data processing requirements increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The method segments genomic sequences into fixed-length k-mer units, transforming complex genomic data into manageable discrete elements. This segmentation allows comprehensive analysis of sequence information while reducing computational complexity through efficient k-mer counting and frequency calculation algorithms that can be implemented with optimized data structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention replaces traditional sequence alignment mechanisms with k-mer frequency counting and statistical analysis. This substitution eliminates the computational burden of pairwise sequence comparison while maintaining high detection accuracy through probabilistic discrimination between species-specific and background k-mer patterns.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11781190B2Discovery of biological signatures of optimized sensitivity and specificity
Publication Date: 2023.10.10 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US11781190B2 patent drawing
  • US11781190B2 patent drawing

AI summary

A bioinformatics method is provided for identifying candidate biological sequences, such as DNA, RNA, and proteins, with high sensitivity and specificity for application in procedures such as PCR and gene and protein sequencing. The method involves categorizing a collection of biological sequences within an out-group and an in-group, identifying the intersection between the in-group and the out-group, the union of the out-group, and a relative complement of sequences that are members of the in-group, but not the out-group. A biological signature for a species of interest with high sensitivity and specificity will be a member of the relative complement that has an out-group frequency of zero.