Merge pull request #54 from nf-core/dev

Get upstream changes

.github/workflows/ci.yml

@@ -29,8 +29,8 @@ jobs:
           - NXF_VER: ""
             NXF_EDGE: "1"
         parameters:
-          - "--longread_clip false"
+          - "--perform_longread_clip false"
-          - "--shortread_clip false"
+          - "--perform_shortread_clipmerge false"
           - "--shortread_clipmerge_tool fastp"
           - "--shortread_clipmerge_tool fastp --shortread_clipmerge_mergepairs --shortread_clipmerge_excludeunmerged"
           - "--shortread_clipmerge_tool fastp --shortread_clipmerge_mergepairs"
@@ -39,6 +39,9 @@ jobs:
           - "--shortread_clipmerge_tool adapterremoval --shortread_clipmerge_mergepairs"
           - "--shortread_complexityfilter_tool bbduk"
           - "--shortread_complexityfilter_tool prinseq"
+          - "--perform_runmerging"
+          - "--perform_runmerging --shortread_clipmerge_mergepairs"
+          - "--shortread_complexityfilter false --perform_shortread_hostremoval"
 
     steps:
       - name: Check out pipeline code

conf/modules.config

@@ -132,6 +132,24 @@ process {
         ]
     }
 
+    withName: BOWTIE2_BUILD {
+        ext.prefix = { "${meta.id}_${meta.run_accession}" }
+        publishDir = [
+            path: { "${params.outdir}/bowtie2/build" },
+            mode: params.publish_dir_mode,
+            pattern: '*.bt2'
+        ]
+    }
+
+    withName: BOWTIE2_ALIGN {
+        ext.prefix = { "${meta.id}_${meta.run_accession}" }
+        publishDir = [
+            path: { "${params.outdir}/bowtie2/align" },
+            mode: params.publish_dir_mode,
+            pattern: '*.{fastq.gz,bam}'
+        ]
+    }
+
     withName: BBMAP_BBDUK {
         ext.args =  [
                 "entropy=${params.shortread_complexityfilter_entropy}",
@@ -161,9 +179,19 @@ process {
         ]
     }
 
+    withName: CAT_FASTQ {
+        ext.prefix = { "${meta.id}" }
+        publishDir = [
+            path: { "${params.outdir}/run_merging/" },
+            mode: params.publish_dir_mode,
+            pattern: '*.fastq.gz',
+            enabled: params.save_runmerged_reads
+        ]
+    }
+
     withName: MALT_RUN {
         ext.args = { "${meta.db_params}" }
-        ext.prefix = { "${meta.id}-${meta.run_accession}-${meta.db_name}" }
+        ext.prefix = params.perform_runmerging ? { "${meta.id}-${meta.db_name}" } : { "${meta.id}-${meta.run_accession}-${meta.db_name}" }
         publishDir = [
             path: { "${params.outdir}/malt/${meta.db_name}" },
             mode: params.publish_dir_mode,
@@ -173,7 +201,7 @@ process {
 
     withName: KRAKEN2_KRAKEN2 {
         ext.args = { "${meta.db_params}" }
-        ext.prefix = { "${meta.id}-${meta.run_accession}-${meta.db_name}" }
+        ext.prefix = params.perform_runmerging ? { "${meta.id}-${meta.db_name}" } : { "${meta.id}-${meta.run_accession}-${meta.db_name}" }
         publishDir = [
             path: { "${params.outdir}/kraken2/${meta.db_name}" },
             mode: params.publish_dir_mode,
@@ -182,12 +210,13 @@ process {
     }
 
     withName: METAPHLAN3 {
+        ext.args = { "${meta.db_params}" }
+        ext.prefix = params.perform_runmerging ? { "${meta.id}-${meta.db_name}" } : { "${meta.id}-${meta.run_accession}-${meta.db_name}" }
         publishDir = [
             path: { "${params.outdir}/metaphlan3/${meta.db_name}" },
             mode: params.publish_dir_mode,
             pattern: '*.{biom,txt}'
         ]
-        ext.prefix = { "${meta.id}-${meta.run_accession}-${meta.db_name}" }
     }
 
     withName: CENTRIFUGE_CENTRIFUGE {

conf/test.config

@@ -28,7 +28,9 @@ params {
     run_malt                      = true
     run_metaphlan3                = true
     run_centrifuge                = true
-    shortread_clipmerge           = true
+    perform_shortread_clipmerge           = true
-    longread_clip                 = false
+    perform_longread_clip                 = false
-    shortread_complexityfilter    = true
+    perform_shortread_complexityfilter    = true
+    perform_shortread_hostremoval         = true
+    shortread_hostremoval_reference       = 'https://raw.githubusercontent.com/nf-core/test-datasets/modules/data/genomics/homo_sapiens/genome/genome.fasta'
 }

modules.json

@@ -9,6 +9,12 @@
             "bbmap/bbduk": {
                 "git_sha": "e745e167c1020928ef20ea1397b6b4d230681b4d"
             },
+            "bowtie2/align": {
+                "git_sha": "e745e167c1020928ef20ea1397b6b4d230681b4d"
+            },
+            "bowtie2/build": {
+                "git_sha": "e745e167c1020928ef20ea1397b6b4d230681b4d"
+            },
             "cat/fastq": {
                 "git_sha": "e745e167c1020928ef20ea1397b6b4d230681b4d"
             },

modules/nf-core/modules/bowtie2/align/main.nf

@@ -0,0 +1,77 @@
+process BOWTIE2_ALIGN {
+    tag "$meta.id"
+    label 'process_high'
+
+    conda (params.enable_conda ? 'bioconda::bowtie2=2.4.4 bioconda::samtools=1.14 conda-forge::pigz=2.6' : null)
+    container "${ workflow.containerEngine == 'singularity' && !task.ext.singularity_pull_docker_container ?
+        'https://depot.galaxyproject.org/singularity/mulled-v2-ac74a7f02cebcfcc07d8e8d1d750af9c83b4d45a:4d235f41348a00533f18e47c9669f1ecb327f629-0' :
+        'quay.io/biocontainers/mulled-v2-ac74a7f02cebcfcc07d8e8d1d750af9c83b4d45a:4d235f41348a00533f18e47c9669f1ecb327f629-0' }"
+
+    input:
+    tuple val(meta), path(reads)
+    path  index
+    val   save_unaligned
+
+    output:
+    tuple val(meta), path('*.bam')    , emit: bam
+    tuple val(meta), path('*.log')    , emit: log
+    tuple val(meta), path('*fastq.gz'), emit: fastq, optional:true
+    path  "versions.yml"              , emit: versions
+
+    when:
+    task.ext.when == null || task.ext.when
+
+    script:
+    def args = task.ext.args ?: ''
+    def args2 = task.ext.args2 ?: ''
+    def prefix = task.ext.prefix ?: "${meta.id}"
+    if (meta.single_end) {
+        def unaligned = save_unaligned ? "--un-gz ${prefix}.unmapped.fastq.gz" : ''
+        """
+        INDEX=`find -L ./ -name "*.rev.1.bt2" | sed 's/.rev.1.bt2//'`
+        bowtie2 \\
+            -x \$INDEX \\
+            -U $reads \\
+            --threads $task.cpus \\
+            $unaligned \\
+            $args \\
+            2> ${prefix}.bowtie2.log \\
+            | samtools view -@ $task.cpus $args2 -bhS -o ${prefix}.bam -
+
+        cat <<-END_VERSIONS > versions.yml
+        "${task.process}":
+            bowtie2: \$(echo \$(bowtie2 --version 2>&1) | sed 's/^.*bowtie2-align-s version //; s/ .*\$//')
+            samtools: \$(echo \$(samtools --version 2>&1) | sed 's/^.*samtools //; s/Using.*\$//')
+            pigz: \$( pigz --version 2>&1 | sed 's/pigz //g' )
+        END_VERSIONS
+        """
+    } else {
+        def unaligned = save_unaligned ? "--un-conc-gz ${prefix}.unmapped.fastq.gz" : ''
+        """
+        INDEX=`find -L ./ -name "*.rev.1.bt2" | sed 's/.rev.1.bt2//'`
+        bowtie2 \\
+            -x \$INDEX \\
+            -1 ${reads[0]} \\
+            -2 ${reads[1]} \\
+            --threads $task.cpus \\
+            $unaligned \\
+            $args \\
+            2> ${prefix}.bowtie2.log \\
+            | samtools view -@ $task.cpus $args2 -bhS -o ${prefix}.bam -
+
+        if [ -f ${prefix}.unmapped.fastq.1.gz ]; then
+            mv ${prefix}.unmapped.fastq.1.gz ${prefix}.unmapped_1.fastq.gz
+        fi
+        if [ -f ${prefix}.unmapped.fastq.2.gz ]; then
+            mv ${prefix}.unmapped.fastq.2.gz ${prefix}.unmapped_2.fastq.gz
+        fi
+
+        cat <<-END_VERSIONS > versions.yml
+        "${task.process}":
+            bowtie2: \$(echo \$(bowtie2 --version 2>&1) | sed 's/^.*bowtie2-align-s version //; s/ .*\$//')
+            samtools: \$(echo \$(samtools --version 2>&1) | sed 's/^.*samtools //; s/Using.*\$//')
+            pigz: \$( pigz --version 2>&1 | sed 's/pigz //g' )
+        END_VERSIONS
+        """
+    }
+}

modules/nf-core/modules/bowtie2/align/meta.yml

@@ -0,0 +1,51 @@
+name: bowtie2_align
+description: Align reads to a reference genome using bowtie2
+keywords:
+  - align
+  - fasta
+  - genome
+  - reference
+tools:
+  - bowtie2:
+      description: |
+        Bowtie 2 is an ultrafast and memory-efficient tool for aligning
+        sequencing reads to long reference sequences.
+      homepage: http://bowtie-bio.sourceforge.net/bowtie2/index.shtml
+      documentation: http://bowtie-bio.sourceforge.net/bowtie2/manual.shtml
+      doi: 10.1038/nmeth.1923
+      licence: ["GPL-3.0-or-later"]
+input:
+  - meta:
+      type: map
+      description: |
+        Groovy Map containing sample information
+        e.g. [ id:'test', single_end:false ]
+  - reads:
+      type: file
+      description: |
+        List of input FastQ files of size 1 and 2 for single-end and paired-end data,
+        respectively.
+  - index:
+      type: file
+      description: Bowtie2 genome index files
+      pattern: "*.ebwt"
+output:
+  - bam:
+      type: file
+      description: Output BAM file containing read alignments
+      pattern: "*.{bam}"
+  - versions:
+      type: file
+      description: File containing software versions
+      pattern: "versions.yml"
+  - fastq:
+      type: file
+      description: Unaligned FastQ files
+      pattern: "*.fastq.gz"
+  - log:
+      type: file
+      description: Aligment log
+      pattern: "*.log"
+authors:
+  - "@joseespinosa"
+  - "@drpatelh"

modules/nf-core/modules/bowtie2/build/main.nf

@@ -0,0 +1,30 @@
+process BOWTIE2_BUILD {
+    tag "$fasta"
+    label 'process_high'
+
+    conda (params.enable_conda ? 'bioconda::bowtie2=2.4.4' : null)
+    container "${ workflow.containerEngine == 'singularity' && !task.ext.singularity_pull_docker_container ?
+        'https://depot.galaxyproject.org/singularity/bowtie2:2.4.4--py39hbb4e92a_0' :
+        'quay.io/biocontainers/bowtie2:2.4.4--py39hbb4e92a_0' }"
+
+    input:
+    path fasta
+
+    output:
+    path 'bowtie2'      , emit: index
+    path "versions.yml" , emit: versions
+
+    when:
+    task.ext.when == null || task.ext.when
+
+    script:
+    def args = task.ext.args ?: ''
+    """
+    mkdir bowtie2
+    bowtie2-build $args --threads $task.cpus $fasta bowtie2/${fasta.baseName}
+    cat <<-END_VERSIONS > versions.yml
+    "${task.process}":
+        bowtie2: \$(echo \$(bowtie2 --version 2>&1) | sed 's/^.*bowtie2-align-s version //; s/ .*\$//')
+    END_VERSIONS
+    """
+}

modules/nf-core/modules/bowtie2/build/meta.yml

@@ -0,0 +1,33 @@
+name: bowtie2_build
+description: Builds bowtie index for reference genome
+keywords:
+  - build
+  - index
+  - fasta
+  - genome
+  - reference
+tools:
+  - bowtie2:
+      description: |
+        Bowtie 2 is an ultrafast and memory-efficient tool for aligning
+        sequencing reads to long reference sequences.
+      homepage: http://bowtie-bio.sourceforge.net/bowtie2/index.shtml
+      documentation: http://bowtie-bio.sourceforge.net/bowtie2/manual.shtml
+      doi: 10.1038/nmeth.1923
+      licence: ["GPL-3.0-or-later"]
+input:
+  - fasta:
+      type: file
+      description: Input genome fasta file
+output:
+  - index:
+      type: file
+      description: Bowtie2 genome index files
+      pattern: "*.bt2"
+  - versions:
+      type: file
+      description: File containing software versions
+      pattern: "versions.yml"
+authors:
+  - "@joseespinosa"
+  - "@drpatelh"

nextflow.config

@@ -55,7 +55,7 @@ params {
     databases = null
 
     // FASTQ preprocessing
-    shortread_clipmerge                     = false
+    perform_shortread_clipmerge             = false
     shortread_clipmerge_tool                = 'fastp'
     shortread_clipmerge_skipadaptertrim     = false
     shortread_clipmerge_mergepairs          = false
@@ -63,11 +63,11 @@ params {
     shortread_clipmerge_adapter1            = null
     shortread_clipmerge_adapter2            = null
     shortread_clipmerge_minlength           = 15
-    longread_clip                           = false
+    perform_longread_clip                   = false
     save_preprocessed_reads                 = false
 
     // Complexity filtering
-    shortread_complexityfilter                           = false
+    perform_shortread_complexityfilter                   = false
     shortread_complexityfilter_tool                      = 'bbduk'
     shortread_complexityfilter_entropy                   = 0.3
     shortread_complexityfilter_bbduk_windowsize          = 50
@@ -76,6 +76,14 @@ params {
     shortread_complexityfilter_prinseqplusplus_dustscore = 0.5
     save_complexityfiltered_reads                        = false
 
+    // run merging
+    perform_runmerging          = false
+    save_runmerged_reads        = false
+
+    // Host Removal
+    perform_shortread_hostremoval     = false
+    shortread_hostremoval_reference = null
+    shortread_hostremoval_index     = null
 
     // MALT
     run_malt                   = false

nextflow_schema.json

@@ -262,15 +262,9 @@
             "type": "string",
             "default": "None"
         },
-        "shortread_clipmerge": {
-            "type": "boolean"
-        },
         "shortread_clipmerge_excludeunmerged": {
             "type": "boolean"
         },
-        "longread_clip": {
-            "type": "boolean"
-        },
         "run_malt": {
             "type": "boolean"
         },
@@ -321,8 +315,7 @@
             "default": 15
         },
         "save_preprocessed_reads": {
-            "type": "boolean",
+            "type": "boolean"
-            "default": false
         },
         "shortread_complexityfilter_tool": {
             "type": "string",
@@ -335,9 +328,6 @@
         "shortread_complexityfilter_bbduk_mask": {
             "type": "boolean"
         },
-        "shortread_complexityfilter": {
-            "type": "boolean"
-        },
         "shortread_complexityfilter_entropy": {
             "type": "number",
             "default": 0.3
@@ -352,8 +342,33 @@
             "default": 0.5
         },
         "save_complexityfiltered_reads": {
-            "type": "boolean",
+            "type": "boolean"
-            "default": false
+        },
+        "save_runmerged_reads": {
+            "type": "boolean"
+        },
+        "perform_shortread_clipmerge": {
+            "type": "boolean"
+        },
+        "perform_longread_clip": {
+            "type": "boolean"
+        },
+        "perform_shortread_complexityfilter": {
+            "type": "boolean"
+        },
+        "perform_runmerging": {
+            "type": "boolean"
+        },
+        "perform_shortread_hostremoval": {
+            "type": "boolean"
+        },
+        "shortread_hostremoval_reference": {
+            "type": "string",
+            "default": null
+        },
+        "shortread_hostremoval_index": {
+            "type": "string",
+            "default": null
         }
     }
 }

subworkflows/local/profiling.nf

@@ -9,8 +9,7 @@ include { METAPHLAN3                  } from '../../modules/nf-core/modules/meta
 
 workflow PROFILING {
     take:
-    shortreads // [ [ meta ], [ reads ] ]
+    reads // [ [ meta ], [ reads ] ]
-    longreads // [ [ meta ], [ reads ] ]
     databases // [ [ meta ], path ]
 
     main:
@@ -23,8 +22,14 @@ workflow PROFILING {
     */
 
     // e.g. output [DUMP: reads_plus_db] [['id':'2612', 'run_accession':'combined', 'instrument_platform':'ILLUMINA', 'single_end':1], <reads_path>/2612.merged.fastq.gz, ['tool':'malt', 'db_name':'mal95', 'db_params':'"-id 90"'], <db_path>/malt90]
-    ch_input_for_profiling = shortreads
+    ch_input_for_profiling = reads
-            .mix( longreads )
+            .map {
+                meta, reads ->
+                    def meta_new = meta.clone()
+                        pairtype = meta_new['single_end'] ? '_se' : '_pe'
+                        meta_new['id'] =  meta_new['id'] + pairtype
+                    [meta_new, reads]
+            }
             .combine(databases)
             .branch {
                 malt:    it[2]['tool'] == 'malt'

subworkflows/local/shortread_fastp.nf

@@ -28,8 +28,8 @@ workflow SHORTREAD_FASTP {
                                         .map {
                                             meta, reads ->
                                                 def meta_new = meta.clone()
-                                                meta_new['single_end'] = 1
+                                                meta_new['single_end'] = true
-                                                [ meta_new, reads ]
+                                                [ meta_new, [ reads ].flatten() ]
                                         }
 
         ch_fastp_reads_prepped = ch_fastp_reads_prepped_pe.mix( FASTP_SINGLE.out.reads )

subworkflows/local/shortread_hostremoval.nf

@@ -0,0 +1,34 @@
+//
+// Remove host reads via alignment and export off-target reads
+//
+
+include { BOWTIE2_BUILD             } from '../../modules/nf-core/modules/bowtie2/build/main'
+include { BOWTIE2_ALIGN             } from '../../modules/nf-core/modules/bowtie2/align/main'
+
+workflow SHORTREAD_HOSTREMOVAL {
+    take:
+    reads     // [ [ meta ], [ reads ] ]
+    reference // /path/to/fasta
+    index     // /path/to/index
+
+    main:
+    ch_versions       = Channel.empty()
+    ch_multiqc_files  = Channel.empty()
+
+    if ( !params.shortread_hostremoval_index ) {
+        ch_bowtie2_index = BOWTIE2_BUILD ( reference ).index
+        ch_versions      = ch_versions.mix( BOWTIE2_BUILD.out.versions )
+    } else {
+        ch_bowtie2_index = index.first()
+    }
+
+    BOWTIE2_ALIGN ( reads, ch_bowtie2_index, true )
+    ch_versions      = ch_versions.mix( BOWTIE2_ALIGN.out.versions.first() )
+    ch_multiqc_files = ch_multiqc_files.mix( BOWTIE2_ALIGN.out.log )
+
+    emit:
+    reads    = BOWTIE2_ALIGN.out.fastq   // channel: [ val(meta), [ reads ] ]
+    versions = ch_versions               // channel: [ versions.yml ]
+    mqc      = ch_multiqc_files
+}
+

workflows/taxprofiler.nf

@@ -11,7 +11,9 @@ WorkflowTaxprofiler.initialise(params, log)
 
 // TODO nf-core: Add all file path parameters for the pipeline to the list below
 // Check input path parameters to see if they exist
-def checkPathParamList = [ params.input, params.databases, params.multiqc_config ]
+def checkPathParamList = [ params.input, params.databases, params.shortread_hostremoval_reference,
+                            params.shortread_hostremoval_index, params.multiqc_config
+                        ]
 for (param in checkPathParamList) { if (param) { file(param, checkIfExists: true) } }
 
 // Check mandatory parameters
@@ -20,6 +22,12 @@ if (params.databases) { ch_databases = file(params.databases) } else { exit 1, '
 if (params.shortread_clipmerge_mergepairs && params.run_malt ) log.warn "[nf-core/taxprofiler] warning: MALT does not accept uncollapsed paired-reads. Pairs will be profiled as separate files."
 if (params.shortread_clipmerge_excludeunmerged && !params.shortread_clipmerge_mergepairs) exit 1, "[nf-core/taxprofiler] error: cannot include unmerged reads when merging not turned on. Please specify --shortread_clipmerge_mergepairs"
 
+if (params.perform_shortread_hostremoval && !params.shortread_hostremoval_reference) { exit 1, "[nf-core/taxprofiler] error: --shortread_hostremoval requested but no --shortread_hostremoval_reference FASTA supplied. Check input." }
+if (!params.shortread_hostremoval_reference && params.shortread_hostremoval_reference_index) { exit 1, "[nf-core/taxprofiler] error: --shortread_hostremoval_index provided but no --shortread_hostremoval_reference FASTA supplied. Check input." }
+
+if (params.shortread_hostremoval_reference ) { ch_reference       = file(params.shortread_hostremoval_reference) }
+if (params.shortread_hostremoval_index     ) { ch_reference_index = file(params.shortread_hostremoval_index    ) } else { ch_reference_index = [] }
+
 /*
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     CONFIG FILES
@@ -43,6 +51,7 @@ include { INPUT_CHECK             } from '../subworkflows/local/input_check'
 include { DB_CHECK                      } from '../subworkflows/local/db_check'
 include { SHORTREAD_PREPROCESSING       } from '../subworkflows/local/shortread_preprocessing'
 include { LONGREAD_PREPROCESSING        } from '../subworkflows/local/longread_preprocessing'
+include { SHORTREAD_HOSTREMOVAL         } from '../subworkflows/local/shortread_hostremoval'
 include { SHORTREAD_COMPLEXITYFILTERING } from '../subworkflows/local/shortread_complexityfiltering'
 include { PROFILING                     } from '../subworkflows/local/profiling'
 
@@ -101,16 +110,17 @@ workflow TAXPROFILER {
     /*
         SUBWORKFLOW: PERFORM PREPROCESSING
     */
-    if ( params.shortread_clipmerge ) {
+    if ( params.perform_shortread_clipmerge ) {
 
         ch_shortreads_preprocessed = SHORTREAD_PREPROCESSING ( INPUT_CHECK.out.fastq ).reads
     } else {
         ch_shortreads_preprocessed = INPUT_CHECK.out.fastq
     }
 
-    if ( params.longread_clip ) {
+    if ( params.perform_longread_clip ) {
         ch_longreads_preprocessed = LONGREAD_PREPROCESSING ( INPUT_CHECK.out.nanopore ).reads
                                         .map { it -> [ it[0], [it[1]] ] }
+        ch_versions = ch_versions.mix(LONGREAD_PREPROCESSING.out.versions.first())
     } else {
         ch_longreads_preprocessed = INPUT_CHECK.out.nanopore
     }
@@ -119,17 +129,63 @@ workflow TAXPROFILER {
         SUBWORKFLOW: COMPLEXITY FILTERING
     */
 
-    if ( params.shortread_complexityfilter ) {
+    if ( params.perform_shortread_complexityfilter ) {
         ch_shortreads_filtered = SHORTREAD_COMPLEXITYFILTERING ( ch_shortreads_preprocessed ).reads
     } else {
         ch_shortreads_filtered = ch_shortreads_preprocessed
     }
 
+    /*
+        SUBWORKFLOW: HOST REMOVAL
+    */
+
+    if ( params.perform_shortread_hostremoval ) {
+        ch_shortreads_hostremoved = SHORTREAD_HOSTREMOVAL ( ch_shortreads_filtered, ch_reference, ch_reference_index ).reads
+        ch_versions = ch_versions.mix(SHORTREAD_HOSTREMOVAL.out.versions.first())
+    } else {
+        ch_shortreads_hostremoved = ch_shortreads_filtered
+    }
+
+    if ( params.perform_runmerging ) {
+
+        ch_reads_for_cat_branch = ch_shortreads_hostremoved
+            .mix( ch_longreads_preprocessed )
+            .map {
+                meta, reads ->
+                    def meta_new = meta.clone()
+                    meta_new.remove('run_accession')
+                    [ meta_new, reads ]
+            }
+            .groupTuple()
+            .map {
+                meta, reads ->
+                    [ meta, reads.flatten() ]
+            }
+            .branch {
+                meta, reads ->
+                // we can't concatenate files if there is not a second run, we branch
+                // here to separate them out, and mix back in after for efficiency
+                cat: ( meta.single_end && reads.size() > 1 ) || ( !meta.single_end && reads.size() > 2 )
+                skip: true
+            }
+
+        ch_reads_runmerged = CAT_FASTQ ( ch_reads_for_cat_branch.cat ).reads
+            .mix( ch_reads_for_cat_branch.skip )
+            .map {
+                meta, reads ->
+                [ meta, [ reads ].flatten() ]
+            }
+
+    } else {
+        ch_reads_runmerged = ch_shortreads_hostremoved
+            .mix( ch_longreads_preprocessed )
+    }
+
     /*
         SUBWORKFLOW: PROFILING
     */
 
-    PROFILING ( ch_shortreads_filtered, ch_longreads_preprocessed, DB_CHECK.out.dbs )
+    PROFILING ( ch_reads_runmerged, DB_CHECK.out.dbs )
     ch_versions = ch_versions.mix( PROFILING.out.versions )
 
     /*
@@ -151,21 +207,30 @@ workflow TAXPROFILER {
     ch_multiqc_files = ch_multiqc_files.mix(CUSTOM_DUMPSOFTWAREVERSIONS.out.mqc_yml.collect())
     ch_multiqc_files = ch_multiqc_files.mix(FASTQC.out.zip.collect{it[1]}.ifEmpty([]))
 
-    if (params.shortread_clipmerge) {
+    if (params.perform_shortread_clipmerge) {
         ch_multiqc_files = ch_multiqc_files.mix( SHORTREAD_PREPROCESSING.out.mqc.collect{it[1]}.ifEmpty([]) )
         ch_versions = ch_versions.mix( SHORTREAD_PREPROCESSING.out.versions )
     }
 
-    if (params.longread_clip) {
+    if (params.perform_longread_clip) {
         ch_multiqc_files = ch_multiqc_files.mix( LONGREAD_PREPROCESSING.out.mqc.collect{it[1]}.ifEmpty([]) )
         ch_versions = ch_versions.mix( LONGREAD_PREPROCESSING.out.versions )
     }
 
-    if (params.shortread_complexityfilter){
+    if (params.perform_shortread_complexityfilter){
         ch_multiqc_files = ch_multiqc_files.mix( SHORTREAD_COMPLEXITYFILTERING.out.mqc.collect{it[1]}.ifEmpty([]) )
         ch_versions = ch_versions.mix( SHORTREAD_COMPLEXITYFILTERING.out.versions )
     }
 
+    if (params.perform_shortread_hostremoval) {
+        ch_multiqc_files = ch_multiqc_files.mix(SHORTREAD_HOSTREMOVAL.out.mqc.collect{it[1]}.ifEmpty([]))
+        ch_versions = ch_versions.mix(SHORTREAD_HOSTREMOVAL.out.versions)
+    }
+
+    if (params.perform_runmerging){
+        ch_versions = ch_versions.mix(CAT_FASTQ.out.versions)
+    }
+
     ch_multiqc_files = ch_multiqc_files.mix( PROFILING.out.mqc )
 
     // TODO create multiQC module for metaphlan