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单细胞工具箱|Cell Ranger-V6.0 开启单细胞之旅(上)

 生信补给站 2021-07-20

Cell Ranger是一个10X genomics公司的单细胞分析软件,将原始的fastq文件生成后续分析的feature-barcode表达矩阵。

其中包括很多模块,本次主要介绍cellranger mkfastq、cellranger count,cellranger aggr 和 cellranger reanalyze四个功能模块。

一 Cell Ranger下载安装

1.1 下载

进入cellranger官网(https://support./)后,发现支持的分析模块有很多,先介绍单细胞转录组。选择单细胞转录组模块,点击进入

软件-下载-选择你想要的cellranger版本,

https://support./single-cell-gene-expression/software/downloads/latest

1)curl ,wget 和 直接网页下载,三种方式均可;

2)记得下载注释文件

3)注意查看md5值(很重要

1.2 安装

Step1:解压下载的软件安装包

#进入文件存放的位置,示例为opt
$ cd /opt
#解压
$ tar -xzvf cellranger-6.0.1.tar.gz

解压缩到一个名为cellranger-6.0.1的新目录,包含Cell Ranger及其依赖项和Cell Ranger脚本。

Step2:同样的方式解压参考文件

$ tar -xzvf refdata-gex-GRCh38-2020-A.tar.gz

Step3:配置环境

将Cell Ranger目录添加到$PATH中,注意路径要准确,示例为/opt ,

$ export PATH=/opt/cellranger-6.0.1:$PATH

为使用方便可以添加到.bashrc文件中。

1.3 测试安装

可以查看一下版本和帮助,或者参考官网的Site Check Script 的方式。

cellranger -V
cellranger -h

下载:https://support./single-cell-gene-expression/software/downloads/latest

安装:https://support./single-cell-gene-expression/software/pipelines/latest/installation

二 mkfastq模块

cellranger使用mkfastq功能来拆分Illumina 原始数据(raw base call (BCL)),输出 FASTQ 文件。

2.1 下载示例数据

点击下载即可

2.2 Running mkfastq with a Simple CSV Samplesheet

1)首先示例矩阵数据解压缩,当前目录下生成cellranger-tiny-bcl-1.2.0文件夹

tar -xvzf cellranger-tiny-bcl-1.2.0.tar.gz

2)Simple CSV Samplesheet文件

格式:三列(Lane、Sample、Index),逗号分隔,不太容易出现格式错误。示例数据cellrangerver -tiny-bcl-simple-1.2.0.csv如下:

Lane,Sample,Index
1,test_sample,SI-TT-D9

Lane

Which lane(s) of the flowcell to process. Can be either a single lane, a range (e.g., 2-4) or '*' for all lanes in the flowcell.

Sample

The name of the sample. This name is the prefix to all the generated FASTQs, and corresponds to the --sample argument in all downstream 10x pipelines.
Sample names must conform to the Illumina bcl2fastq naming requirements. Only letters, numbers, underscores and hyphens area allowed; no other symbols, including dots (".") are allowed.

Index

The 10x sample index that was used in library construction, e.g., SI-TT-D9 or SI-GA-A1

3)run mkfastq

需要安装且配置bcl2fastq软件

$ cellranger mkfastq --id=cellranger-tiny-bcl-1.2.0 \
--run=/path/to/cellranger-tiny-bcl-1.2.0 \
--csv=cellranger-tiny-bcl-simple-1.2.0.csv

id :即为解压后的文件夹名字

run:为解压后的文件夹的绝对路径

在id名的新文件夹中既有生成的fastq文件了,可以用于后续的count分析。

另一种请参考https://support./single-cell-gene-expression/software/pipelines/latest/using/mkfastq

三 count 模块

此处使用转录组数据进行count分析,通过fastq文件得到细胞和基因的定量结果。

3.1 必要参数

$ cellranger count --id=sample345 \
--transcriptome=/opt/refdata-gex-GRCh38-2020-A \
--fastqs=/home/jdoe/runs/HAWT7ADXX/outs/fastq_path \
--sample=mysample \
--expect-cells=1000 \

--id= 名称
--fastqs= fastq.gz文件保存的绝对路径
--sample= fastq.gz文件名"-"之前的字段
--transcriptome= 参考基因组路径

--expect-cells= 期望细胞数(可选)

3.2 参数列表

参数详细介绍详见:

https://support./single-cell-gene-expression/software/pipelines/latest/using/count#args中的Command-Line Argument Reference 部分

可以注意下以下参数:

--expect-cells

(optional) Expected number of recovered cells. Default: 3,000 cells.

和实验匹配

--nosecondary

(optional) Add this flag to skip secondary analysis of the feature-barcode matrix (dimensionality reduction, clustering and visualization). Set this if you plan to use cellranger reanalyze or your own custom analysis.

仅获得表达矩阵,不进行后续的降维,聚类和可视化分析

--chemistry

(optional) Assay configuration. NOTE: by default the assay configuration is detected automatically, which is the recommended mode. You should only specify chemistry if there is an error in automatic detection. Select one of:

  • auto for auto-detection (default),

  • ...


3.3 结果文件

结果文件列表以及简要描述说明

File Name

Description


web_summary.html

Run summary metrics and charts in HTML format

网页简版报告以及可视化

metrics_summary.csv

Run summary metrics in CSV format


possorted_genome_bam.bam

Reads aligned to the genome and transcriptome annotated with barcode information


possorted_genome_bam.bam.bai

Index for possorted_genome_bam.bam


filtered_feature_bc_matrix

Filtered feature-barcode matrices containing only cellular barcodes in MEX format. (In Targeted Gene Expression samples, the non-targeted genes are not present.)

过滤掉的barcode信息

filtered_feature_bc_matrix_h5.h5

Filtered feature-barcode matrices containing only cellular barcodes in HDF5 format. (In Targeted Gene Expression samples, the non-targeted genes are not present.)

过滤掉的barcode信息HDF5 format;

raw_feature_bc_matrices

Unfiltered feature-barcode matrices containing all barcodes in MEX format

原始barcode信息

raw_feature_bc_matrix_h5.h5

Unfiltered feature-barcode matrices containing all barcodes in HDF5 format

原始barcode信息HDF5 format

analysis

Secondary analysis data including dimensionality reduction, cell clustering, and differential expression


molecule_info.h5

Molecule-level information used by cellranger aggr to aggregate samples into larger datasets


cloupe.cloupe

Loupe Browser visualization and analysis file

Loupe Cell Browser 输入文件

feature_reference.csv

(Feature Barcode only) Feature Reference CSV file


target_panel.csv

(Targeted GEX only) Targed panel CSV file


参考资料:https://support./single-cell-gene-expression/software/pipelines/latest/using/mkfastq

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