Non-acyclic Genome Graph Alignment on Heterogeneous Systems

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Solution Overview

Problem

Current sequence-to-graph alignment methods struggle with efficiency and accuracy when handling non-acyclic genome graphs, which are necessary for representing inter-individual and intra-individual variability in genomic data.

Innovation Solution

The method employs heterogeneous computing resources (CPUs and GPUs) to align sequence reads with non-acyclic sequence-labelled genome graphs, using a dual representation of the graph to enable intra-sequence parallelism and an adaptive bandwidth heuristic to optimize computation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If non-acyclic genome graphs are used to represent genomic variability, then alignment accuracy is improved, but computational complexity and processing time increase significantly

Engineering Contradiction:
Improvealignment accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the non-acyclic genome graph into multiple acyclic subgraphs (DAGs) by identifying and removing cyclic regions. Each subgraph can be processed independently using efficient DAG-based alignment algorithms, thereby maintaining alignment accuracy while reducing computational complexity. The segmentation allows the system to handle complex genomic variations without the full computational burden of processing the entire non-acyclic graph at once.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by pre-processing the genome graph to identify cyclic regions and prepare acyclic subgraphs before the actual alignment process. This includes building indexes for the acyclic portions and pre-computing alignment parameters, which reduces the computational load during the main alignment phase and improves overall processing efficiency while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If fine-grained non-acyclic graphs are used, then alignment precision is improved, but execution time increases significantly

Engineering Contradiction:
Improvealignment precisionVSAvoidexecution time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent divides the fine-grained non-acyclic graph into multiple acyclic subgraphs, allowing parallel processing of alignment tasks. Each subgraph can be aligned independently and simultaneously, which maintains the high precision benefits of fine-grained representation while significantly reducing total execution time through parallel computation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by focusing computational resources on aligning reads to specific acyclic subgraphs that are most relevant to the query sequences. Rather than exhaustively processing the entire graph with equal intensity, the method selectively processes portions of the graph that provide the most value for alignment precision, thereby reducing overall execution time while maintaining high precision where needed.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If exact alignment algorithms are used for non-acyclic graphs, then alignment quality is improved, but memory cost and execution time increase

Engineering Contradiction:
Improvealignment qualityVSAvoidmemory cost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the genome graph into acyclic subgraphs, which can be processed using memory-efficient DAG-based alignment algorithms. This segmentation allows exact alignment to be performed on smaller, manageable portions of the graph, reducing the peak memory requirements compared to processing the entire non-acyclic graph with exact alignment algorithms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates simplified copies or representations of the acyclic subgraphs that are optimized for memory-efficient processing. These copies contain only the necessary information for alignment tasks, allowing exact alignment algorithms to run with reduced memory footprints while maintaining alignment quality.

Inventive Principle:
Principle #26Copying

4Productivity

If DAG-ification is applied to non-acyclic graphs, then processing efficiency is improved, but alignment quality degrades

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidalignment quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the non-acyclic graph into acyclic subgraphs that preserve the original graph's structural information and alignment properties. By carefully identifying boundaries between cyclic and acyclic regions, the segmentation maintains alignment quality at the subgraph level while enabling efficient DAG-based processing, thus avoiding the quality degradation associated with forced DAG-ification of the entire graph.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing strategies to different parts of the graph: acyclic subgraphs are processed using efficient DAG-based algorithms, while cyclic regions are handled with specialized approaches that preserve alignment quality. This local quality approach ensures that each region is processed with the most appropriate method, maintaining overall alignment quality while improving processing efficiency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20250191690A1Methods for the alignment of sequence reads to nonacyclic genome graphs on heterogeneous computing system
Publication Date: 2025.06.12 POLITECNICO DI MILANO
  • US20250191690A1 patent drawing
  • US20250191690A1 patent drawing
  • US20250191690A1 patent drawing

AI summary

The disclosed embodiments concern methods, apparatus, systems, and computer program products for computing the best alignment score between a set of query sequences and a non-acyclic sequence-labelled reference genome graph comprising a processor and non-transitory memory. In an embodiment, said computing is performed employing an alignment algorithm suitable for non-acyclic graph that leverages inter-sequence and intra-sequence parallelism, executed on a heterogeneous computing system, containing at least a CPU (Central Processing Unit) and a GPU (Graphics Processing Units).