Variant Detection in Electropherogram Data

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Solution Overview

Problem

Sanger sequencing technologies face challenges in accurately interpreting mixed-base observations due to instrument noise and low-quality electropherogram data, leading to difficulties in accurately aligning mixed-base sequences to reference sequences and recovering true sequences in heterozygous conditions.

Innovation Solution

A method is developed to analyze electropherogram data by identifying mixed bases, validating errors, and determining variants, utilizing a combination of algorithms such as the Stripped Smith-Waterman algorithm and Peak Detection module to improve the accuracy of variant calling and mixed-base alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated algorithms are used to interpret electropherogram data, then processing speed increases, but accuracy decreases due to difficulty in characterizing algorithmic features without extensive training data

Engineering Contradiction:
Improveprocessing speedVSAvoidinterpretation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary quality assessment and trimming of electropherogram traces before variant calling. By pre-processing the data to remove low-quality regions and normalize traces, the algorithm creates cleaner input data that improves subsequent interpretation accuracy without requiring extensive training datasets.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system introduces an intermediate quality scoring mechanism that evaluates electropherogram traces before automated variant calling. This intermediary quality assessment layer filters out poor-quality data and flags regions requiring manual review, bridging the gap between automated processing and accuracy requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If quality trimming is applied to remove low-quality regions, then noise is reduced, but sequence information is lost

Engineering Contradiction:
Improvenoise reductionVSAvoidsequence information loss
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The system applies quality trimming selectively to specific regions of the electropherogram rather than uniformly across the entire trace. By identifying and preserving high-quality regions while removing only the problematic low-quality ends, the system maintains maximum sequence information while eliminating noise.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system uses a conservative trimming approach that removes only the minimum necessary low-quality regions rather than aggressively trimming large portions. This partial action preserves more sequence information while still achieving sufficient noise reduction for accurate variant calling.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If mixed-base observations are called to represent heterozygous positions, then biological variation is captured, but false positives increase due to instrument noise

Engineering Contradiction:
Improvebiological variation detectionVSAvoidfalse positive rate
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system implements a feedback mechanism where quality metrics from the electropherogram trace are used to adjust the stringency of mixed-base calling. In regions with high noise levels or poor quality metrics, the system raises the threshold for calling mixed bases, reducing false positives while maintaining sensitivity in high-quality regions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts variant calling parameters based on local quality metrics of the electropherogram trace. By changing thresholds and sensitivity settings according to the observed data quality, the system optimizes the balance between detecting true heterozygous variants and avoiding false positives from instrument noise.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10557821B2Methods and systems for variant detection
Publication Date: 2020.02.11 LIFE TECHNOLOGIES CORP
  • US10557821B2 patent drawing
  • US10557821B2 patent drawing
  • US10557821B2 patent drawing

AI summary

In one exemplary embodiment, a method for detecting variants in electropherogram data is provided. The method includes receiving electropherogram data from an instrument and analyzing the electropherogram data to identify mixed bases in the electropherogram data. The method further includes validating the identified mixed bases. Then the method includes determining variants in the electropherogram data based on the validated mixed bases.