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Updated: Feb 24, 2026

Formaldehyde-assisted Isolation of Regulatory Elements to Measure Chromatin Accessibility in Mammalian Cells
Published on: April 2, 2018
chromVAR: inferring transcription-factor-associated accessibility from single-cell epigenomic data
Alicia N Schep1,2, Beijing Wu1,2, Jason D Buenrostro3,4
1Department of Genetics, Stanford University School of Medicine, Stanford, California, USA.
chromVAR is a new R package that analyzes sparse single-cell ATAC-seq data. It accurately clusters cell profiles and identifies sequence motifs linked to chromatin accessibility variations.
Area of Science:
- Genomics
- Computational Biology
- Epigenetics
Background:
- Single-cell ATAC-seq (scATAC) generates sparse data, posing challenges for traditional analytical methods.
- Understanding cell-type-specific chromatin accessibility is crucial for deciphering gene regulation.
Purpose of the Study:
- To develop a robust computational tool for analyzing sparse scATAC-seq data.
- To enable accurate clustering and motif discovery from scATAC-seq profiles.
Main Methods:
- Development of chromVAR, an R package implementing a novel algorithm.
- Estimation of chromatin accessibility gain/loss within motif- or annotation-defined peak sets.
- Incorporation of bias correction for technical variations in scATAC-seq data.
Main Results:
- chromVAR facilitates accurate clustering of single-cell ATAC-seq profiles.
- The package effectively characterizes known and de novo sequence motifs associated with chromatin accessibility.
- Demonstrated utility in analyzing sparse chromatin accessibility data.
Conclusions:
- chromVAR provides a powerful solution for analyzing challenging sparse scATAC-seq datasets.
- The tool enhances the ability to identify regulatory elements and cell populations based on chromatin accessibility patterns.
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