🚀 EPIC: Comprehensive nascent RNA pipeline enhancements

## Summary This epic tracks the implementation of advanced features from leading nascent RNA analysis pipelines (PEPPRO, NRSA/eNRSA, BidirectionalFlow, MuMerge) into nf-core/nascent. These enhancements will transform the pipeline from basic transcript identification to a comprehensive platform for nascent transcription analysis. ## Background Analysis of six industry-leading nascent RNA pipelines revealed critical gaps in our current implementation and identified proven solutions for: - **Quality Control**: PEPPRO's 5 novel QC metrics specifically designed for nascent RNA - **Performance**: eNRSA's 20x speed improvements and 8x memory reduction - **Analysis Depth**: NRSA's enhancer prioritization and multi-strategy target gene assignment - **Specialized Detection**: BidirectionalFlow's multi-algorithm consensus approach - **Statistical Rigor**: MuMerge's probabilistic region merging framework ## Implementation Roadmap ### 🔥 Phase 1: Core Quality Control & Performance (High Priority) Essential features that address immediate user needs and pipeline robustness. - [ ] #[ISSUE_NUMBER] Add comprehensive nascent RNA QC metrics module - [ ] #[ISSUE_NUMBER] Add serial alignment preprocessing for contamination removal - [ ] #[ISSUE_NUMBER] Improve UMI handling and deduplication options - [ ] #[ISSUE_NUMBER] Implement RNA degradation ratio calculation - [ ] #[ISSUE_NUMBER] Integrate seqOutBias for enzymatic bias correction **Expected Impact**: 30-40% performance improvement, comprehensive QC assessment, reduced false positives ### 📈 Phase 2: Advanced Analysis Capabilities (Medium Priority) Enhanced analytical features that expand pipeline utility for regulatory genomics. - [ ] #[ISSUE_NUMBER] Add NRSA enhancer prioritization and target gene assignment - [ ] #[ISSUE_NUMBER] Generate comprehensive HTML QC reports with interactive plots - [ ] #[ISSUE_NUMBER] Implement eNRSA algorithmic optimizations for speed and memory - [ ] #[ISSUE_NUMBER] Implement alternative TSS/TTS and readthrough detection **Expected Impact**: Enhanced enhancer analysis, better reporting, improved isoform detection ### 🔬 Phase 3: Specialized & Statistical Methods (Long-term) Advanced features for sophisticated analyses and multi-sample studies. - [ ] #[ISSUE_NUMBER] Add MuMerge statistical framework for region combination - [ ] #[ISSUE_NUMBER] Implement BidirectionalFlow multi-algorithm consensus approach - [ ] #[ISSUE_NUMBER] Enhance visualization capabilities and genome browser integration **Expected Impact**: Statistical rigor for multi-sample studies, bidirectional transcription detection ### 📋 Phase 4: Integration & Documentation (Meta) Coordination and documentation for successful feature integration. - [ ] #[ISSUE_NUMBER] Plan integration roadmap for nascent RNA pipeline enhancements - [ ] #[ISSUE_NUMBER] Comprehensive documentation update for enhanced pipeline features ## Success Metrics ### Performance Improvements - [ ] 30-40% reduction in processing time (serial alignment) - [ ] 20x speed improvement for count matrix generation (eNRSA optimizations) - [ ] 8x memory usage reduction - [ ] 15-20% improvement in peak calling accuracy (bias correction) ### Quality Control Enhancement - [ ] 5 new nascent-specific QC metrics implemented - [ ] Interactive HTML reports with publication-ready figures - [ ] Comprehensive RNA integrity assessment - [ ] Library complexity projections ### Analysis Capabilities - [ ] Multi-strategy enhancer-gene assignment - [ ] Alternative isoform detection - [ ] Bidirectional transcription identification - [ ] Statistical region merging for multi-sample studies ### User Experience - [ ] Comprehensive documentation for all new features - [ ] Clear configuration examples and best practices - [ ] Improved error handling and user feedback - [ ] Backward compatibility maintained ## Technical Requirements ### Container/Environment Updates - [ ] seqOutBias and dependencies - [ ] Flash for paired-end processing - [ ] Preseq for complexity projections - [ ] Additional R packages for statistical methods ### Configuration Schema Updates - [ ] QC metric thresholds - [ ] Serial alignment options - [ ] Bias correction parameters - [ ] Advanced analysis toggles ### Testing Strategy - [ ] Comprehensive test datasets covering all data types - [ ] Performance benchmarking suite - [ ] QC metric validation - [ ] Integration testing for new modules ## Dependencies & Risks ### External Dependencies - Availability of reference tools (PEPPRO, eNRSA source code) - Container compatibility for new software - nf-core module standards compliance ### Technical Risks - Memory/compute requirements for advanced features - Backward compatibility with existing configurations - Integration complexity between multiple new modules ### Mitigation Strategies - Phased implementation with thorough testing - Optional feature flags for advanced capabilities - Comprehensive documentation and examples - Community feedback integration ## References - **PEPPRO**: [Genome Biology 2021](https://genomebiology.biomedcentral.com/articles/10.1186/s13059-021-02349-4) - **NRSA**: [BMC Genomics 2018](https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-018-5016-z) - **eNRSA**: [GigaScience 2024](https://academic.oup.com/gigascience/article/doi/10.1093/gigascience/giaf071/8185776) - **BidirectionalFlow**: [GitHub Repository](https://github.com/Dowell-Lab/Bidirectional-Flow) - **MuMerge**: [GitHub Repository](https://github.com/Dowell-Lab/mumerge) ## Communication ### Status Updates Weekly progress updates will be posted to this issue with: - Completed features and their impact - Blockers and resolution strategies - Performance benchmarking results - Community feedback integration ### Review Process - Each phase requires review before proceeding to next - Performance metrics validation required - Community testing and feedback incorporation - Documentation completeness verification --- **Project Timeline**: Estimated 4-6 months for complete implementation **Target Release**: nf-core/nascent v3.0.0 **Project Lead**: @[YOUR_USERNAME] *This epic represents a significant advancement in nascent RNA analysis capabilities, positioning nf-core/nascent as the definitive pipeline for nascent transcription studies.*