Structural Variant Detection Using Amplicon Read Mapping
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Solution Overview
Problem
Current nucleic acid sequencing technologies face challenges in detecting large structural variants, such as deletions, due to their size exceeding read lengths, making it difficult to span and accurately identify these variations.
Innovation Solution
A system and method for detecting structural variants involve amplifying nucleic acid samples using primer pairs flanking breakpoint regions, generating amplicons, and mapping reads to a reference sequence to identify and classify variants, including deletions, by aligning reads to modified reference sequences containing putative structural variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If short sequence reads are used for high throughput sequencing, then sequencing throughput and cost-effectiveness are improved, but the ability to detect large structural variants deteriorates because read length is insufficient to span the variant regions
Solution Approach 1:
The patent segments the detection process into multiple independent analyses: (1) mapping reads to the reference genome to identify potential structural variants, (2) separately analyzing read pairs for structural variant evidence, and (3) integrating results from both approaches. This segmentation allows each analysis method to operate independently with optimized parameters, overcoming the limitation of short read lengths by combining multiple lines of evidence rather than relying on a single read to span the entire variant.
Solution Approach 2:
The patent introduces an intermediary computational framework that bridges the gap between short reads and large structural variants. This framework uses split-read analysis to identify partial mappings within reads that overlap with variant boundaries, and read-pair analysis to detect abnormal insertion sizes or orientations. These intermediary signals from multiple reads collectively provide evidence for structural variants that no single short read could detect alone.
2Reliability
If reads are mapped to the reference genome to identify structural variants, then detection sensitivity is improved, but computational resources and processing time are consumed
Solution Approach 1:
The patent performs preliminary filtering and prioritization steps before comprehensive structural variant analysis. It first identifies potential structural variant regions through initial scanning of mapping patterns and read pair characteristics, then focuses detailed analysis only on these candidate regions. This preliminary action reduces the computational burden by avoiding exhaustive analysis of the entire genome, thereby decreasing processing time while maintaining detection sensitivity.
Solution Approach 2:
The patent extracts and analyzes specific features relevant to structural variant detection separately from the complete sequencing data. It extracts split-read signals, read-pair insertion sizes, and orientation patterns as distinct analytical components. By taking out only the relevant features for structural variant detection rather than processing all raw data uniformly, the system reduces computational overhead while preserving detection sensitivity.
Data Source
AI summary
Systems and method for identifying long deletions can obtain sequencing information for a plurality of amplicons in and around a potential region from a nucleic acid sample. The sequencing information can include a plurality of reads that can be mapped to a reference sequence. Using information, such as where reads map to a reference sequence and relative abundance of reads for the amplicons, structural variants can be identified and a determination can be made if the nucleic acid sample is homozygous or heterozygous for the structural variant.