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CAdir: Joint clustering of cells and genes for single-cell transcriptomics with visualization-driven cluster quality
Clemens Kohl1, Martin Vingron1
1Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany.
Plos Computational Biology
|June 30, 2026
Summary
CAdir is a new clustering algorithm for single-cell RNA sequencing data. It automatically determines the number of cell clusters and identifies marker genes, improving interpretability and quality assessment.
Area of Science:
- Computational biology
- Genomics
- Bioinformatics
Background:
- Single-cell RNA sequencing (scRNA-seq) clustering aims to group similar cells.
- Existing algorithms often fail to identify marker genes or determine cluster numbers unsupervisedly.
- Current quality assessment relies on potentially misleading low-dimensional embeddings (e.g., UMAP, t-SNE).
Purpose of the Study:
- To develop an interpretable clustering algorithm for scRNA-seq data.
- To enable unsupervised inference of cluster number and identification of cluster-specific genes.
- To provide diagnostic tools for evaluating clustering quality.
Main Methods:
- Developed CAdir, a novel clustering algorithm.
- Utilizes correspondence analysis (CA) geometry to cluster cells and genes.
- Employs cluster direction angles in CA space to infer and refine cluster numbers.
- Integrates diagnostic plots for feedback on clustering decisions.
Main Results:
- CAdir infers the number of clusters and identifies defining marker genes.
- The algorithm provides interpretable diagnostic plots for quality assessment.
- Benchmarking shows comparable performance to state-of-the-art methods.
- CAdir is scalable to large scRNA-seq datasets.
Conclusions:
- CAdir offers an improved, interpretable approach to scRNA-seq data clustering.
- It addresses limitations of existing methods by automating cluster number inference and marker gene identification.
- The diagnostic tools enhance the reliability of clustering results.
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