Questions tagged [scrnaseq]

Use this tag for questions related to single-cell RNA-seq.

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3
votes
2answers
443 views

PCA plot shows big difference but not many differentially expressed genes are found

I got a PCA plot of bulk RNA-seq experiment that looks the following way: It was generated by the following code: ...
2
votes
3answers
3k views

How can I obtain the percentage gene expression per identity class in Seurat as further processible numbers (e.g. matrix)?

I am analysing my single cell RNA seq data with the Seurat package. I want to know if there is a possibilty to obtain the percentage expression of a list of genes per identity class, as actual numbers ...
13
votes
2answers
2k views

How to decide number of neighbors and resolution for Louvain clustering

I am using Louvain clustering (1,2) to cluster cells in scRNAseq data, as implemented by scanpy. One of the parameter required for this kind of clustering is the number of neighbors used to construct ...
1
vote
1answer
74 views

How to identify latent variables in single-cell RNA-Seq data

I have a single-cell RNASeq sample, in which I'd like to identify latent variables (e.g. response to stress) that I think might be affecting the clustering. The approach I was planning to use is to ...
2
votes
1answer
152 views

Identifying mutually **exclusive** gene sets

I am interested in identifying gene pairs (or better: sets of genes) whose expression is mutually exclusive. Ideally, both genes (or gene sets) would be widely expressed but I am also interested in ...
1
vote
1answer
1k views

Reading multiple raw files in Seurat

I have multiple single cell samples to analyze and I'm following the instructions in Satija Lab's website. I want to merge all the count files from all the samples at once, and associate the metadata ...
0
votes
1answer
56 views

Processed spliced and unspliced count matrices for existing scRNA-seq atlases

Before I do this myself... Is there any compiled batch-corrected dataset of the major scRNA-seq atlases (Mouse Cell Atlas, Mouse Organogenesis Atlas, Mouse Gastrulation Atlas, Tabula Muris, Tabula ...
5
votes
3answers
7k views

Script to allow gene set enrichment analysis of 10x genomics data in R

I have 10x single cell RNA seq data. Which R package is best suited for analysis of the 10x data matrix. What is the script to prepare the data for downstream GSEA analysis. I have already processed ...
0
votes
1answer
33 views

Calculating celltype proportion changes between conditions in single-cell data

I want to test for significance between differences in cell count between conditions. I have 2 conditions (N, T), 3 donors (samples) each, and four cell types (A-D) as shown in the example below. I ...
1
vote
2answers
2k views

Trim Seurat object to contain expression info only for selected genes

I'm working with some large Seurat objects (MOCA, MCA, Tabula Muris) studying gene coexpression, and I'm running into memory issues. Is it possible to remove all genes in a Seurat object that are ...
0
votes
1answer
3k views

Seurat VlnPlot presenting expression of multiple genes in a single cluster

Seurat VlnPlots are most commonly used to visualize differences in any given gene expression across multiple clusters or cell types. For example: ...
0
votes
1answer
2k views

How to calculate the number of cells in different cell clusters with Seurat v3?

I was supposed to use the code below to get the number of cells per cluster. The code works with Seurat version 2, but while using version 3 I got the error ...
0
votes
2answers
532 views

how to generate an scRNA counts file

I have barcodes.tsv, genes.tsv and matrix.mtx file from my RNA seq data and I want to generate a scRNA counts files using R. When I tried using the readMM function, ...
1
vote
0answers
32 views

Human Cell Atlas - cell annotations

Human Cell Atlas Preview Datasets have been available for a while now (there was some discussion about that earlier). However, although the raw data is available, cell labels are not (for example, ...
2
votes
1answer
908 views

How to load and split my two individual datasets when integrating datasets in Seurat?

I want to do comparative analyses of my two individual single cell RNA-Seq datasets in Seurat. And I load and list my data as follows: ...
2
votes
2answers
92 views

How to best detect the "peaks" in RNA-seq data that are not assigned to any gene?

I encountered that many reads from single-cell RNA seq data were lost in the analysis because not assigned to any gene (genome: galgal6). I am trying to find an approach than could give me all the "...
3
votes
1answer
55 views

public multi-modal single-cell data

There is a scRNAseq Bioconductor package with a few different example scRNA-seq datasets. Are there any R packages that offer multiple modalities of single-cell data? For example, hashtags or ADTs or ...
1
vote
3answers
846 views

Understanding Single Cell RNAseq Plots

I have just started some single cell RNAseq analysis with 500 cells. I have used Seurat for analysis. Following the guideline I have generated few plots. Now I am trying to understand how to read ...
1
vote
0answers
147 views

PCA on large sparse matrix of single cell RNA-seq

I received a large sc-RNA-seq data matrix, as of the nature of sc-RNA-seq compared to bulk-RNA-seq the data matrix is very sparse. Moreover, due to the fact that this is single cell data the cell ...
2
votes
1answer
2k views

How I can reproduce this heat map

I have single cell RNA-seq on 8 time points. I have clustered each time point to 2-3 clusters by seurat. I also have a list of differentially expressed genes between all my 1562 cells in 8 time points....
3
votes
1answer
261 views

how to filter out cell after doing QC

I was wondering that the threshold that we set after doing QC in Seurat. there is an example ...
3
votes
1answer
208 views

Problem: "Pair-end" reads scRNA seq data (Drop-seq)

In case of Drop-seq, we have paired end data. Read 1: Cell code + UMI (unique molecule identifier) Read 2: The transcript information But I have a problem/doubt with the sample I am working on. ...
2
votes
1answer
123 views

Single Cell RNA seq Analysis for low input Cells?

I am having a single cell RNA seq data from ~500 Cells. I do understand this number is very low for present day analysis tools like Seurat. So, I want to know what if one have a such a small number of ...
1
vote
1answer
396 views

Hierarchical clustering for outlier detection - single cell RNASeq & WGCNA

I wish to conduct WGCNA on a single cell RNASeq dataset and, when choosing the optimal beta parameter after running pickSoftThreshold am presented with a rather ...
1
vote
0answers
256 views

Normalization of single cell RNASeq data with ERCC spike-ins

I wish to normalize a scRNASeq dataset with respect to ERCC spike-ins, where "for some of the samples, ERCC spike-in RNA was added to the lysis buffer" and was wondering how to do so? I have seen ...
1
vote
2answers
185 views

How are UMIs used to dedupulicate in Drop-seq tools?

The module DigitalExpression which is part of the popular Drop-seq tools digitally count gene transcripts. The manual is not very clear on how exactly it resolves ...
2
votes
1answer
1k views

How to highlight specific cells in Seurat 2.4

I used Seurat 2.4 on our scRNA dataset to obtain the following tSNE plot.I was able to successfully extract cell IDs from the different clusters, and generate gene expression profiles. The analysis, ...
4
votes
3answers
879 views

How to compare transcriptomic profiles of two cell types (single cell RNA-seq)?

I found this interesting Single RNA-seq data set in GEO, but I am not sure how to analyze it appropriately. They have deposited transcriptomic profiles of human and mouse pancreatic islets (...
5
votes
3answers
3k views

Is it possible to merge scRNAseq data from experiments with different design?

I have 4 different single-cell RNAseq experiments, each one representing a different sample of cell type population. I'd like to merge them to a single dataset. However, different cell types are ...
5
votes
1answer
811 views

PCA vs tSNE in single cell RNA-seq

What makes tSNE being the preferred dimensional reduction for visualization in single cell RNA-seq over PCA? I am aware that tSNE works better at showing local structures and fails to capture global ...
-1
votes
1answer
62 views

How I normalize these two sets of data

I have average log fold change for a cluster of cells versus another cluster of cells by Seurat like below ...
2
votes
1answer
755 views

Why do I have >10,000 cells in the 10X matrix produced by cellranger?

In my scRNA seq experiment, single-cell libraries were generated using the GemCode Single-Cell Instrument and Single Cell 3′ Library & Gel Bead Kit v2 and Chip Kit (10x Genomics) according to the ...
3
votes
1answer
201 views

How do I prevent the FeatureHeatmap function from the Seurat package, from sorting my data groups in alphabetical order when plotting data?

How can I prevent a function from sorting my data groups (factors) in alphabetical order without affecting the integrity of the data? I am analysing single cell RNA sequencing data using Seurat 2.3.4. ...
0
votes
2answers
195 views

residual Squared Coefficient of Variation (rCV²) vs Distance to Median (DM)

I am working with single cell RNA-seq data. I obtained the squared coefficient of variation (CV²) as a measure of gene expression variability: I want a metric to express gene expression noise that ...
19
votes
3answers
2k views

What is the actual cause of excessive zeroes in single cell RNA-seq data? Is it PCR?

First, sorry if I am missing something basic - I am a programmer recently turned bioinformatician so I still don't know a lot of stuff. This is a cross post with a Biostars question hope that's not ...
1
vote
1answer
186 views

Discordance in gene signature behavior between bulk and single-cell RNASeq

The objective of the following analysis is to identify an activation signature of a specific phenotype on bulk RNASeq and to apply it to single-cell RNA-Seq, in order to identify the population of ...
3
votes
1answer
1k views

Understanding PCHeatmap outputs

I am currently trying to understand the purpose of these PCHeatmaps - part of the seurat package in R: All the online documentation I have searched for has only ...
2
votes
1answer
129 views

scRNASeq expression matrix with decimal values

I am trying to replicate some results of a scRNASeq experiment and, when I looked at the data provided by the author, I noticed that some of the counts in the expression matrix are represented as ...
1
vote
2answers
85 views

Using preprocessing/alignment functions on the server

I am new to bash and the processes behind cluster computing in general and need some help with understanding some basics. After looking all over the internet and this forum (+ askUbuntu) I found ...
2
votes
2answers
121 views

scRNA-seq differential transcript usage

Many of the modern gene-quantification tools (Salmon/Kallisto) output transcript-level (as opposed to gene-level) data. All of the scRNA-seq analysis I have seen just uses the gene-level values. I ...
3
votes
1answer
2k views

How to set the position of groups in a Seurat object on a FeatureHeatmap plot

I am analysing singe cell sequence data and I have followed this tutorial, https://satijalab.org/seurat/pbmc3k_tutorial.html to perform QC and various differential analyses using the Seurat package on ...
2
votes
1answer
1k views

Visualising gene expression across cell type and conditions in one plot, in Single Cell Sequencing data

I am new to single cell sequencing data analysis but I have basic programming background in R and python. I want to be able to plot differential expression of two genes, Gene1 and Gene2, across three ...
3
votes
2answers
3k views

Separate boxplots for multiple violin plot

I am using the following function from seurat package to generate multiple violon plots and I am interested in adding box plots to them but it doesn't work when I have plotted different data at once. ...
5
votes
1answer
771 views

How to normalise scRNASeq data for differential expression analysis

I wish to perform differential expression analysis for cluster-specific gene expression in single-cell data (with a tool such as MAST or SCDE). I have data for 3 biological replicates. I performed ...
3
votes
1answer
541 views

scRNA-seq, 10x cellranger pipelines

I'm starting to do sc-rnaseq using 10x cellranger pipelines, and i add TdTomato sequence to mouse reference genome and add an entry in the gtf. My code is But when I makref, it remindered that: ...
5
votes
1answer
742 views

No counts for added gene in cellranger (scRNA-seq)

I have a set of scRNA-seq samples enriched with FACS for cells expressing a specific gene reporter (TdTomato). In particular the gene I want to report has positive counts in the resulting matrix for ...
2
votes
2answers
243 views

Can I get the graph generated by cellranger

I’ve run the cellranger analysis pipeline on single cell RNASeq datasets. I can import the matrix and graph-based clusters into R. Doing this I can optimise the dimension reduction and plot cells with ...
2
votes
1answer
757 views

What process and input data is required for a cellranger reference transcriptome?

I'm analysing single-cell RNA-Seq data using the 10X Genomics cellranger platform. While they provide reference data for Mouse and Humans, other species require a ...
5
votes
1answer
647 views

Derive a GTF containing protein coding genes from a GTF file with Exons and CDS

Why I need a compatible file I’m trying to run velocyto with the R package to analyse RNA velocity (cell trajectories) with single cell RNASeq data. I have performed single cell analysis from 10x ...
2
votes
1answer
73 views

RCurl issue when installing SCnorm

I am working on the Rivanna cluster that is of SLURM-type. Because of that I do not have write permissions and need to install ...