Cell Ranger requires FASTQ files as input, which typically come from running one of Illumina's demultiplexing software, bcl2fastq or BCL Convert. However, it is possible to use FASTQ files from other sources, such as a published dataset, or the 10x Genomics bamtofastq tool.

For experiments where only gene expression data are present, here are the arguments available for specifying which FASTQ files cellranger count or cellranger vdj should use:

For Feature Barcode experiments, separate libraries for the Gene Expression reads and the Feature Barcode reads are generated. In this case, you must construct a CSV file indicating the input data folder, sample name, and library type of each input library. Then pass this file to cellranger count using the --libraries flag. See Libraries CSV page for details on how to construct the libraries.csv file.

Here are the columns available in the [libraries] section of the multi config CSV for specifying which FASTQ files cellranger multi should use:

There are many ways bcl-convert, bcl2fastq and mkfastq can be used, resulting in a wide range of potential file names and locations as the output.

To serve as inputs for cellranger, FASTQ files should conform to the naming conventions of bcl-convert, bcl2fastq and mkfastq:

[Sample Name]_S1_L00[Lane Number] _[Read Type]_001.fastq.gz

-OR-

[Sample Name]_S1_[Read Type]_001.fastq.gz

Where Read Type is one of:

• I1: Sample index read (optional)
• I2: Sample index read (optional)
• R1: Read 1
• R2: Read 2

The FASTQ files are specified by providing the path to the folder containing them (via the fastqs column) and their Illumina sample name (via the fastq_id column) and optionally restricting the selection further by specifying the lanes of interest.

Finding the right FASTQ files to process and the right arguments to process those files as desired can be confusing. To assist users, this page illustrates examples of how to handle common scenarios involving different FASTQ file folder hierarchies.

• In an output folder from bcl-convert, bcl2fastq or mkfastq (fastq_path) and:
  • Scenario 1: In a subdirectory next to Reports and Stats folders, with expected sample name prefixes.
  • Scenario 2: Within multiple folders per sample index, like "SI-GA-A1_1" and "SI-GA-A1_2".
  • Scenario 3: In the same directory as the Reports and Stats folders.
• In a different folder:
  • Scenario 4: I don't see Reports or Stats anywhere. The files are named like "MySample_S1_L001_I1_001.fastq.gz"

• Consistent with bcl-convert, bcl2fastq or mkfastq , e.g. "mysample_S1_L001_I1_001.fastq.gz" (see above).
• Scenario 5: Like "read-I1-AAAAAAA_lane-001-chunk-001.fastq.gz".
• Scenario 6: Unlike any of the above examples.

My FASTQs are in an output folder from mkfastq or bcl2fastq, in a subdirectory next to Reports and Stats folders, with expected sample name prefixes.

How did I get here?

By running mkfastq with a simple CSV layout file or Illumina Experiment Manager sample sheet, or by running bcl-convert or bcl2fastq directly (with an IEM sample sheet) on a flow cell. If you ran mkfastq, your files will be in a (MKFASTQ_ID)/outs/fastq_path folder and your file hierarchy probably looks something like this:

Copy
MKFASTQ_ID
├── MAKE_FASTQS_CS
└── outs
    └── fastq_path
        └── HFLC5BBXX
            ├── test_sample1
            │   ├── test_sample1_S1_L001_I1_001.fastq.gz
            │   ├── test_sample1_S1_L001_R1_001.fastq.gz
            │   ├── test_sample1_S1_L001_R2_001.fastq.gz
            │   ├── test_sample1_S1_L002_I1_001.fastq.gz
            │   ├── test_sample1_S1_L002_R1_001.fastq.gz
            │   ├── test_sample1_S1_L002_R2_001.fastq.gz
            │   ├── test_sample1_S1_L003_I1_001.fastq.gz
            │   ├── test_sample1_S1_L003_R1_001.fastq.gz
            │   └── test_sample1_S1_L003_R2_001.fastq.gz
            ├── test_sample2
            │   ├── test_sample2_S2_L001_I1_001.fastq.gz
            │   ├── test_sample2_S2_L001_R1_001.fastq.gz
            │   ├── test_sample2_S2_L001_R2_001.fastq.gz
            │   ├── test_sample2_S2_L002_I1_001.fastq.gz
            │   ├── test_sample2_S2_L002_R1_001.fastq.gz
            │   ├── test_sample2_S2_L002_R2_001.fastq.gz
            │   ├── test_sample2_S2_L003_I1_001.fastq.gz
            │   ├── test_sample2_S2_L003_R1_001.fastq.gz
            │   └── test_sample2_S2_L003_R2_001.fastq.gz
            ├── Reports
            ├── Stats
            ├── Undetermined_S0_L001_I1_001.fastq.gz
            ...
            └── Undetermined_S0_L003_R2_001.fastq.gz

If you ran bcl2fastq directly, then the output root folder would be where fastq_path is in the hierarchy above.

"Expected sample name prefixes" means you have one set of FASTQ files per sample, prefixed with the name of the sample as it appears in the simple CSV layout file or IEM sample sheet. Other situations described later on this page deal with the presence of four separate sets of files (four "samples" from bcl2fastq's point of view) per single biological sample/library.

For more information on the naming conventions, please visit Illumina's support site or refer to the bcl2fastq User Guide. The scenario where your files do not conform to the naming convention is described in a different section in this page.

Cell Ranger count/vdj arguments

The table below describes the arguments you would pass into any analysis pipeline to target the right FASTQ fastq files in this scenario. Be sure to substitute the capitalized text as appropriate. Also note that in most cases you will be passing a single sample into any given pipeline. Exceptions to this are described in the documentation for the individual pipelines. The "All Samples" entries in this table are provided for technical completeness.

Cell Ranger multi config CSV arguments

The arguments you would pass into any analysis pipeline to target the right FASTQ files in this scenario are described below. Be sure to substitute the capitalized text as appropriate. Also note that in most cases you will be passing a single sample into any given pipeline. Exceptions to this are described in the documentation for the individual pipelines.

Gene Expression and V(D)J (mkfastq), one flowcell

Copy
[libraries]
fastq_id,fastqs,feature_types
test_sample1,MKFASTQ_ID/outs/fastq_path,Gene Expression
test_sample2,MKFASTQ_ID/outs/fastq_path,VDJ

Gene Expression and V(D)J (mkfastq), multiple flowcells

Copy
[libraries]
fastq_id,fastqs,feature_types
test_sample1,MKFASTQ_ID/outs/fastq_path1,Gene Expression
test_sample2,MKFASTQ_ID/outs/fastq_path2,VDJ

Gene Expression and V(D)J (bcl2fastq direct)

Copy
[libraries]
fastq_id,fastqs,feature_types
test_sample1,/PATH/TO/bcl2fastq_output,Gene Expression
test_sample2,/PATH/TO/bcl2fastq_output,VDJ

My FASTQs are in an output folder from mkfastq or bcl2fastq, but there are multiple folders per sample index, like "SI-GA-A1_1" and "SI-GA-A1_2".

How did I get here?

An input sample sheet was likely used that explicitly separated the four oligos in a 10x sample index set into four separate sample names. You may see a file hierarchy like this:

Copy
bcl2fastq_output
    ├── HFLC5BBXX
    ├── SI-GA-A1_1
    │   ├── SI-GA-A1_1_S1_L001_I1_001.fastq.gz
    │   ├── SI-GA-A1_1_S1_L001_R1_001.fastq.gz
    │   └── SI-GA-A1_1_S1_L001_R2_001.fastq.gz
    ├── SI-GA-A1_2
    │   ├── SI-GA-A1_2_S2_L001_I1_001.fastq.gz
    │   ├── SI-GA-A1_2_S2_L001_R1_001.fastq.gz
    │   └── SI-GA-A1_2_S2_L001_R2_001.fastq.gz
    ├── SI-GA-A1_3
    │   ├── SI-GA-A1_3_S3_L001_I1_001.fastq.gz
    │   ├── SI-GA-A1_3_S3_L001_R1_001.fastq.gz
    │   └── SI-GA-A1_3_S3_L001_R2_001.fastq.gz
    ├── SI-GA-A1_4
    │   ├── SI-GA-A1_4_S4_L001_I1_001.fastq.gz
    │   ├── SI-GA-A1_4_S4_L001_R1_001.fastq.gz
    │   └── SI-GA-A1_4_S4_L001_R2_001.fastq.gz
    ├── Reports
    ├── Stats
    ├── Undetermined_S0_L001_I1_001.fastq.gz
    ├── Undetermined_S0_L001_R1_001.fastq.gz
    └── Undetermined_S0_L001_R2_001.fastq.gz

You probably want to be able to merge All samples from the SI-GA-A1 index into a single analysis. If you only run one index at a time, you will see a smaller number of reads than expected, which may translate to lower coverage or cell count than you expect for your experiment.

Cell Ranger count/vdj arguments

Cell Ranger multi config CSV arguments

Process all SI-GA-A1 reads in a single analysis

Copy
[libraries]
fastq_id,fastqs,feature_types
SI-GA-A1_1,MKFASTQ_ID/outs/fastq_path,Gene Expression
SI-GA-A1_2,MKFASTQ_ID/outs/fastq_path,Gene Expression
SI-GA-A1_3,MKFASTQ_ID/outs/fastq_path,Gene Expression
SI-GA-A1_4,MKFASTQ_ID/outs/fastq_path,Gene Expression

Only process the first sample index

Copy
[libraries]
fastq_id,fastqs,feature_types
SI-GA-A1_1,MKFASTQ_ID/outs/fastq_path,
Gene Expression

My FASTQs are in an output folder from mkfastq or bcl2fastq, in the same directory as the Reports and Stats folders.

How did I get here?

An Illumina Experiment Manager-formatted sample sheet was used with either no entry or a blank entry for the Sample_Project column. Your hierarchy likely looks something like this:

Copy
fastq_path
    ├── Reports
    ├── Stats
    ├── test_sample_S1_L001_I1_001.fastq.gz
    ├── test_sample_S1_L001_R1_001.fastq.gz
    ├── test_sample_S1_L001_R2_001.fastq.gz
    ├── test_sample_S1_L002_I1_001.fastq.gz
    ├── test_sample_S1_L002_R1_001.fastq.gz
    ├── test_sample_S1_L002_R2_001.fastq.gz
    ├── test_sample_S1_L003_I1_001.fastq.gz
    ├── test_sample_S1_L003_R1_001.fastq.gz
    ├── test_sample_S1_L003_R2_001.fastq.gz
    ├── Undetermined_S0_L001_I1_001.fastq.gz
    ...
    └── Undetermined_S0_L003_R2_001.fastq.gz

This is fine; you would use the same arguments as if the FASTQs were organized into subfolders within the output folder.

Cell Ranger count/vdj arguments

Cell Ranger multi config CSV arguments

Process test_sample from all lanes (mkfastq)

Copy
[libraries]
fastq_id,fastqs,feature_types
test_sample,MKFASTQ_ID/outs/fastq_path,Gene Expression

Process test_sample from lane 1 only (mkfastq)

Copy
[libraries]
fastq_id,fastqs,lanes,feature_types
test_sample,MKFASTQ_ID/outs/fastq_path,1,Gene Expression

My FASTQs are in a different folder; I don't see Reports or Stats anywhere. The files are named like "MySample_S1_L001_I1_001.fastq.gz".

How did I get here?

FASTQ files have likely been transferred from either a bcl-convert, bcl2fastq or mkfastq run into another folder. They still retain the names assigned by the software, which is a combination of sample name, sample order, lane, read type, and chunk. Your file hierarchy may look like this:

Copy
PROJECT_FOLDER
     ├── MySample_S1_L001_I1_001.fastq.gz
     ├── MySample_S1_L001_R1_001.fastq.gz
     ├── MySample_S1_L001_R2_001.fastq.gz
     ├── MySample_S1_L002_I1_001.fastq.gz
     ├── MySample_S1_L002_R1_001.fastq.gz
     └── MySample_S1_L002_R2_001.fastq.gz

Cell Ranger count/vdj arguments

Cell Ranger multi config CSV arguments

Process MySample from all lanes

Copy
[libraries]
fastq_id,fastqs,feature_types
MySample,/PATH/TO/PROJECT_FOLDER,Gene Expression

Process MySample from lane 1 only

Copy
[libraries]
fastq_id,fastqs,lanes,feature_types
test_sample,/PATH/TO/PROJECT/FOLDER,1,Gene Expression

My FASTQs are named like "read-I1-AAAAAAA_lane-001-chunk-001.fastq.gz".

How did I get here?

The 10x demux pipeline was used to demultiplex the flowcell instead of mkfastq. This pipeline has been deprecated and cellranger no longer directly supports using FASTQ files in this layout. Please contact [email protected] for assistance.

My FASTQs are not named like any of the above examples.

How did I get here?

You likely received files that were processed through a proprietary LIMS system, which employs its own naming conventions.

10x pipelines need files named in the bcl2fastq convention in order to run properly. You will need to determine which file corresponds to which sample and which read type, likely by consulting your sequencing core or the individual who demultiplexed your flowcell.

It is likely that these files were initially processed with bcl2fastq. Once you track down their origin, you must rename the files (according to format described above).

Cell Ranger count/vdj arguments

After you have renamed those files into that format, you will use the following arguments:

Cell Ranger multi config CSV arguments

Process SAMPLENAME from all lanes

Copy
[libraries]
fastq_id,fastqs,feature_types
SAMPLENAME,/PATH/TO/PROJECT_FOLDER,Gene Expression

Process SAMPLENAME from lane 1 only

Copy
[libraries]
fastq_id,fastqs,lanes,feature_types
test_sample,/PATH/TO/PROJECT/FOLDER,1,Gene Expression