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Updated: Mar 23, 2026
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G2-seq: A High Throughput Sequencing-based Technique for Identifying Late Replicating Regions of the Genome
Published on: March 22, 2018
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GMAP and GSNAP for Genomic Sequence Alignment: Enhancements to Speed, Accuracy, and Functionality.
Thomas D Wu1, Jens Reeder1, Michael Lawrence1
1Genentech, South San Francisco, CA, USA.
Methods in Molecular Biology (Clifton, N.J.)
|March 24, 2016
Summary
The GMAP and GSNAP genome alignment programs now handle longer reads and larger datasets with improved genomic representations and algorithms. These enhancements facilitate biological discoveries through advanced sequence alignment capabilities.
Area of Science:
- Bioinformatics
- Computational Biology
- Genomics
Background:
- The GMAP and GSNAP programs are essential tools for aligning RNA-Seq and DNA-Seq data to reference genomes.
- Advances in sequencing technology necessitate continuous improvement in alignment software to handle longer reads and larger data volumes.
Purpose of the Study:
- To detail the recent enhancements made to the GMAP and GSNAP alignment programs.
- To highlight improvements in genomic representation, algorithms, and functionality for next-generation sequencing data.
Main Methods:
- Implemented SIMD instructions for efficient sequence comparison and dynamic programming.
- Developed compressed genomic hash tables and enhanced suffix arrays (ESAs) for faster data access.
- Introduced greedy match-and-extend algorithms and segment chaining for improved alignment accuracy.
Main Results:
- Successfully adapted GMAP/GSNAP for large genomes (>4 billion bp) and complex genomic features like circular chromosomes.
- Enhanced handling of ambiguous splicing, indel positions, and paired-end read merging.
- Integrated programs into R/Bioconductor packages (gmapR, HTSeqGenie) for pipeline accessibility.
Conclusions:
- The upgraded GMAP and GSNAP programs offer robust and efficient solutions for modern genomic data analysis.
- These advancements in sequence alignment tools accelerate the discovery of novel biological phenomena.
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