Explore Workflows

The original [BioWardrobe's](https://biowardrobe.com) [PubMed ID:26248465](https://www.ncbi.nlm.nih.gov/pubmed/26248465) **ChIP-Seq** basic analysis workflow for a **single-read** experiment with Trim Galore. _Trim Galore_ is a wrapper around [Cutadapt](https://github.com/marcelm/cutadapt) and [FastQC](http://www.bioinformatics.babraham.ac.uk/projects/fastqc/) to consistently apply adapter and quality trimming to FastQ files, with extra functionality for RRBS data. In outputs it returns coordinate sorted BAM file alongside with index BAI file, quality statistics of the input FASTQ file, reads coverage in a form of BigWig file, peaks calling data in a form of narrowPeak or broadPeak files, islands with the assigned nearest genes and region type, data for average tag density plot (on the base of BAM file). Workflow starts with step *fastx\_quality\_stats* from FASTX-Toolkit to calculate quality statistics for input FASTQ file. At the same time `bowtie` is used to align reads from input FASTQ file to reference genome *bowtie\_aligner*. The output of this step is unsorted SAM file which is being sorted and indexed by `samtools sort` and `samtools index` *samtools\_sort\_index*. Based on workflow’s input parameters indexed and sorted BAM file can be processed by `samtools rmdup` *samtools\_rmdup* to get rid of duplicated reads. If removing duplicates is not required the original input BAM and BAI files return. Otherwise step *samtools\_sort\_index\_after\_rmdup* repeat `samtools sort` and `samtools index` with BAM and BAI files. Right after that `macs2 callpeak` performs peak calling *macs2\_callpeak*. On the base of returned outputs the next step *macs2\_island\_count* calculates the number of islands and estimated fragment size. If the last one is less that 80bp (hardcoded in the workflow) `macs2 callpeak` is rerun again with forced fixed fragment size value (*macs2\_callpeak\_forced*). If at the very beginning it was set in workflow input parameters to force run peak calling with fixed fragment size, this step is skipped and the original peak calling results are saved. In the next step workflow again calculates the number of islands and estimates fragment size (*macs2\_island\_count\_forced*) for the data obtained from *macs2\_callpeak\_forced* step. If the last one was skipped the results from *macs2\_island\_count\_forced* step are equal to the ones obtained from *macs2\_island\_count* step. Next step (*macs2\_stat*) is used to define which of the islands and estimated fragment size should be used in workflow output: either from *macs2\_island\_count* step or from *macs2\_island\_count\_forced* step. If input trigger of this step is set to True it means that *macs2\_callpeak\_forced* step was run and it returned different from *macs2\_callpeak* step results, so *macs2\_stat* step should return [fragments\_new, fragments\_old, islands\_new], if trigger is False the step returns [fragments\_old, fragments\_old, islands\_old], where sufix \"old\" defines results obtained from *macs2\_island\_count* step and sufix \"new\" - from *macs2\_island\_count\_forced* step. The following two steps (*bamtools\_stats* and *bam\_to\_bigwig*) are used to calculate coverage on the base of input BAM file and save it in BigWig format. For that purpose bamtools stats returns the number of mapped reads number which is then used as scaling factor by bedtools genomecov when it performs coverage calculation and saves it in BED format. The last one is then being sorted and converted to BigWig format by bedGraphToBigWig tool from UCSC utilities. Step *get\_stat* is used to return a text file with statistics in a form of [TOTAL, ALIGNED, SUPRESSED, USED] reads count. Step *island\_intersect* assigns genes and regions to the islands obtained from *macs2\_callpeak\_forced*. Step *average\_tag\_density* is used to calculate data for average tag density plot on the base of BAM file.

https://github.com/datirium/workflows.git

Path: workflows/trim-chipseq-se.cwl

Branch/Commit ID: c5bae2ca862c764911b83d1f15ff6af4e2a0db28

https://github.com/genome/analysis-workflows.git

Path: definitions/subworkflows/fastq_to_bqsr.cwl

Branch/Commit ID: a7838a5ca72b25db5c2af20a15f34303a839980e

https://github.com/genome/analysis-workflows.git

Path: definitions/subworkflows/sequence_to_bqsr_mouse.cwl

Branch/Commit ID: 3f3b186da9bf82a5e2ae74ba27aef35a46174ebe

https://github.com/common-workflow-language/cwl-utils.git

Path: testdata/step-valuefrom2-wf_v1_2.cwl

Branch/Commit ID: 0ad6983898f0d9001fe0f416f97c4d8b940e384a

https://github.com/common-workflow-language/cwl-v1.2.git

Path: tests/count-lines18-wf.cwl

Branch/Commit ID: c7c97715b400ff2194aa29fc211d3401cea3a9bf

https://github.com/common-workflow-language/cwl-v1.2.git

Path: tests/search.cwl

Branch/Commit ID: 57baec040c99d7edef8242ef51b5470b1c82d733

Packed ID: main

Pairwise comparison

https://github.com/ncbi/pgap.git

Path: task_types/tt_kmer_compare_wnode.cwl

Branch/Commit ID: 42df0c0f9a4e5697abadd9cb52440691fafc8f5d

https://github.com/common-workflow-language/cwl-utils.git

Path: testdata/record-output-wf_v1_0.cwl

Branch/Commit ID: c1875d54dedc41b1d2fa08634dcf1caa8f1bc631

A basic analysis workflow for paired-end ChIP-Seq experiments with a spike-in control. These sequencing library prep methods are chromatin mapping technologies compared to the ChIP-Seq methodology. Its primary benefits include 1) length filtering, 2) a higher signal-to-noise ratio, and 3) built-in normalization for between sample comparisons. This workflow utilizes the tool MACS2 which calls enriched regions in the target sequence data by identifying the top regions by area under a poisson distribution (of the alignment pileup). ### __Inputs__ *General Info (required\*):* - Experiment short name/Alias* - a unique name for the sample (e.g. what was used on tubes while processing it) - Cells* - sample cell type or organism name - Conditions* - experimental condition name - Catalog # - catalog number for cells from vender/supplier - Primary [genome index](https://scidap.com/tutorials/basic/genome-indices) for peak calling* - preprocessed genome index of sample organism for primary alignment and peak calling - Secondary [genome index](https://scidap.com/tutorials/basic/genome-indices) for spike-in normalization* - preprocessed genome index of spike-in organism for secondary alignment (of unaligned reads from primary alignment) and spike-in normalization, default should be E. coli K-12 - FASTQ file for R1* - read 1 file of a pair-end library - FASTQ file for R2* - read 2 file of a pair-end library *Advanced:* - - Number of bases to clip from the 3p end - used by bowtie aligner to trim <int> bases from 3' (right) end of reads - Number of bases to clip from the 5p end - used by bowtie aligner to trim <int> bases from 5' (left) end of reads - Call samtools rmdup to remove duplicates from sorted BAM file? - toggle on/off to remove duplicate reads from analysis - Fragment Length Filter will retain fragments between set base pair (bp) ranges for peak analysis - drop down menu - `default_below_1000` retains fragments <1000 bp - `histones_130_to_300` retains fragments between 130-300 bp - `TF_below_130` retains fragments <130 bp - Max distance (bp) from gene TSS (in both directions) overlapping which the peak will be assigned to the promoter region - default set to `1000` - Max distance (bp) from the promoter (only in upstream directions) overlapping which the peak will be assigned to the upstream region - default set to `20000` - Number of threads for steps that support multithreading - default set to `2` ### __Outputs__ Intermediate and final downloadable outputs include: - IGV with gene, BigWig (raw and normalized), and stringent peak tracks - quality statistics and visualizations for both R1/R2 input FASTQ files - coordinate sorted BAM file with associated BAI file for primary alignment - read pileup/coverage in BigWig format (raw and normalized) - cleaned bed files (containing fragment coordinates), and spike-in normalized peak-called BED files (also includes \"narrow\" and \"broad\" peaks). - stringent peak call bed file with nearest gene annotations per peak ### __Data Analysis Steps__ 1. Trimming the adapters with TrimGalore. - This step is particularly important when the reads are long and the fragments are short - resulting in sequencing adapters at the ends of reads. If adapter is not removed the read will not map. TrimGalore can recognize standard adapters, such as Illumina or Nextera/Tn5 adapters. 2. Generate quality control statistics of trimmed, unmapped sequence data 3. (Optional) Clipping of 5' and/or 3' end by the specified number of bases. 4. Mapping reads to primary genome index with Bowtie. - Only uniquely mapped reads with less than 3 mismatches are used in the downstream analysis. Results are then sorted and indexed. Final outputs are in bam/bai format, which are also used to extrapolate effects of additional sequencing based on library complexity. 5. (Optional) Removal of duplicates (reads/pairs of reads mapping to exactly the same location). - This step is used to remove reads overamplified during amplification of the library. Unfortunately, it may also remove \"good\" reads. We usually do not remove duplicates unless the library is heavily duplicated. 6. Mapping unaligned reads from primary alignment to secondary genome index with Bowtie. - This step is used to obtain the number of reads for normalization, used to scale the read count pileups from the primary alignment used for peak calling. After normalization, sample pileups/peak may then be appropriately compared to one another assuming an equal use of spike-in material during library preparation. 7. Formatting alignment file to account for fragments based on paired-end BAM. - Generates a filtered and normalized bed file to be used as input for peak calling. 8. Call enriched regions using MACS2. - This step called peaks (broad and narrow) using the MACS2 tool with default parameters and no normalization to a control sample. 9. Generation and formatting of output files. - This step collects read, alignment, and peak statistics, as well asgenerates BigWig coverage/pileup files for display on the browser using IGV. The coverage shows the number of fragments that cover each base in the genome both normalized and unnormalized to the calculated spike-in scaling factor.

https://github.com/datirium/workflows.git

Path: workflows/trim-chipseq-pe-spike.cwl

Branch/Commit ID: 93b844a80f4008cc973ea9b5efedaff32a343895

https://github.com/common-workflow-language/cwl-utils.git

Path: testdata/workflow_input_sf_expr_array.cwl

Branch/Commit ID: e78db9870cb744fe36674f43b3223c688e9989e1