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Updated: Apr 19, 2026

Targeted DNA Methylation Analysis by Next-generation Sequencing
Published on: February 24, 2015
QuASAR: quantitative allele-specific analysis of reads
Chris T Harvey1, Gregory A Moyerbrailean1, Gordon O Davis1
1Center for Molecular Medicine and Genetics, Department of Obstetrics and Gynecology, Wayne State University, 540 E Canfield, Scott Hall, Detroit, MI 48201, USA and Department of Biostatistics, University of Michigan, Ann Arbor, MI 48109, USA.
QuASAR infers genotypes and analyzes allele-specific expression (ASE) from RNA-seq data, even without prior genotype information. This method accounts for genotype uncertainty and sequencing errors, offering a powerful tool for genetic variation studies.
Area of Science:
- Genomics
- Bioinformatics
- Statistical Genetics
Background:
- Expression quantitative trait loci (eQTL) studies identify genetic variants regulating gene expression but are costly.
- Allele-specific expression (ASE) analysis offers a cost-effective alternative for detecting genetic variation effects on gene expression within individuals.
- Existing methods lack joint inference of genotypes and ASE, especially when genotype data is unavailable or uncertain.
Purpose of the Study:
- To develop a novel statistical learning method for jointly inferring heterozygous genotypes and allele-specific expression (ASE) from RNA-seq data.
- To address the challenge of genotype uncertainty in ASE analysis.
- To provide a tool that can perform ASE analysis even when genotype information is not readily available.
Main Methods:
- Introduced QuASAR (quantitative allele-specific analysis of reads), a method for joint genotype inference and ASE analysis.
- Incorporated parameters to model base-call errors and allelic over-dispersion.
- Accounted for uncertainty in genotype calls during ASE inference.
Main Results:
- Validated QuASAR using experimental data with available high-quality genotypes.
- Demonstrated QuASAR's efficacy in ASE analysis without prior genotype information using datasets with varying sequencing depths.
- Confirmed QuASAR as a powerful tool for ASE analysis in scenarios with limited or no genotype data.
Conclusions:
- QuASAR effectively integrates genotype inference with ASE analysis, enhancing the utility of RNA-seq data.
- The method's ability to handle genotype uncertainty and sequencing errors makes it robust.
- QuASAR provides a valuable solution for studying genetic variation and its impact on gene expression, particularly when traditional eQTL studies are infeasible.

