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Hamilton, N. H.

Publications and source records attributed to Hamilton, N. H..

2 recordsLinked to original sources

Genome-Wide Uncertainty-Moderated Extraction of Signal Annotations from Multi-Sample Functional Genomics Data

Multi-sample functional genomics experiments should reveal reproducible regulatory activity, but locus- and sample-specific noise can obscure biological signals in sequencing data. We introduce Consenrich for genome-wide estimation of epigenomic signals across multiple samples. To encourage robustness and sensitivity, the state-space model underlying Consenrich accounts for positional observation variances to determine shrinkage toward predictions from a smooth process model over genomic coordinates. We first apply Consenrich to ATAC-seq and ChIP-seq datasets and demonstrate its ability for robust signal recovery. We then utilize Consenrich upstream of a class-imbalanced differential accessibility analysis in an Alzheimer's cohort of twenty samples and show that it improves the breadth of relevant biological insights. Software is available at https://github.com/nolan-h-hamilton/Consenrich.

genomics↗

ROCCO: A Robust Method for Detection of Open Chromatin via Convex Optimization

MotivationAnalysis of open chromatin regions across multiple samples from two or more distinct conditions can determine altered gene regulatory patterns associated with biological phenotypes and complex traits. The ATAC-seq assay allows for tractable genome-wide open chromatin profiling of large numbers of samples. Stable, broadly applicable genomic annotations of open chromatin regions are not available. Thus, most studies first identify open regions using peak calling methods for each sample independently. These are then heuristically combined to obtain a consensus peak set. Reconciling sample-specific peak results post hoc from larger cohorts is particularly challenging, and informative spatial features specific to open chromatin signals are not leveraged effectively. ResultsWe propose a novel method, ROCCO, that determines consensus open chromatin regions across multiple samples simultaneously. ROCCO employs robust summary statistics and solves a constrained optimization problem formulated to account for both enrichment and spatial dependence of open chromatin signal data. We show this formulation admits attractive theoretical and conceptual properties as well as superior empirical performance compared to current methodology. Availability and ImplementationSource code, documentation, and usage demos for ROCCO are available on GitHub at: https://github.com/nolan-h-hamilton/ROCCO. ROCCO can also be installed as a standalone binary utility using pip/PyPI. Contactnolanh@email.unc.edu or tsfurey@email.unc.edu. Supplementary InformationSupplementary material is available with this submission. Additional resources that may aid readers are available in the ROCCO GitHub repository.

bioinformatics↗