In sccallahan/WARPqpcr: Web App and R Package for qPCR
knitr::opts_chunk$set(
collapse = TRUE,
comment = "#>",
fig.path = "man/figures/README-",
out.width = "100%"
)
WARPqpcr
knitr::include_graphics("man/figures/WARPqpcr.png")
Web App and R Package for qPCR (WARPqpcr) provides functionality for analyzing RT-qPCR and ChIP-qPCR data and generating plots of results.
The goal of this package is to allow rapid, reproducible analysis of qPCR data, particularly in the molecular biology setting, to provide easy functions for visualizing results, and to provide a tool for selecting the best housekeeping gene from a list of candidates. Many of the functions in this package use ReadqPCR and NormqPCR packages for calculations and data structures, and the housekeeping gene stability is an implementation of an existing method (references for all of this are at the end of the README!)
Accessing the Web App
In addition to being available as an R package, WARPqpcr is available as a web application. This web app requires no knowledge of R or programming in general to use. Users only need to upload their samplesheet (format described below), choose an analysis type, then fill out a few texts fields. The analysis is automatically run, and results (.txt files with CT values, ddCT values, etc. and .png files of relative expression) are available for download as a zip file.
CLICK HERE to go to the shinyapps.io page containing the web app.
CLICK HERE for information on how to use the web application.
Installation
You can install the released version of WARPqpcr from this repo with:
# install devtools if needed -- must have for installing from github
install.packages("devtools")
library(devtools)
# now install WARPqpcr
install_github("sccallahan/WARPqpcr")
NB: Some linux systems may have difficulty installing some dependencies, particularly the rgl package (a dependency quite a way down the chain). This can be fixed by running the following lines in terminal:
``` {bash, eval=FALSE}
apt-get install libx11-dev mesa-common-dev libglu1-mesa-dev
## Quick navigation
* [Samplesheet format description](https://github.com/sccallahan/WARPqpcr#some-notes-about-samplesheet-format-and-methods)
* [RT-qPCR single replicate](https://github.com/sccallahan/WARPqpcr#example-for-rt-qcpr-single-replicate-data)
* [RT-qPCR biological replicate](https://github.com/sccallahan/WARPqpcr#example-for-rt-qpcr-biological-replicate-data)
* [Housekeeping gene stability](https://github.com/sccallahan/WARPqpcr#example-for-selecting-most-stable-housekeeping-gene)
* [ChIP-qPCR single replicate](https://github.com/sccallahan/WARPqpcr#example-for-chip-qpcr-single-replicate-data)
* [ChIP-qPCR biological replicate](https://github.com/sccallahan/WARPqpcr#example-for-chip-qpcr-biological-replicate-data)
* [References](https://github.com/sccallahan/WARPqpcr#references)
* [Acknowledgements](https://github.com/sccallahan/WARPqpcr#acknowledgments)
* [Citation information](https://github.com/sccallahan/WARPqpcr#citation)
## Some notes about samplesheet format and methods
#### Samplesheet format and reading in data
The format for the samplesheet is described in the [ReadqPCR documentation.](https://www.bioconductor.org/packages/release/bioc/vignettes/ReadqPCR/inst/doc/ReadqPCR.pdf) In short, it requires 5 columns in a *tab-delimited* file:
* **Well.** The well letter/number.
* **Plate.** The plate number.
* **Sample.** The name of the sample being analayzed. It is *critical* that biological replicates have unique identifiers (e.g. "WT_1" and "WT_2" instead of just "WT" for both). Samples with identical names will be treated as technical replicates.
* **Detector.** The gene/region being measured. In the case of ChIP-qPCR, regions should be entered as "factor_regionName" (e.g. input_R1, H3K27ac_R1, CTCF_R1, IgG_R1, etc. for each region).
* **Cq.** The Ct/Cq value for the well. These values *must* be either numerics or NAs.
The `readSampleSheet` function assumes that the data is formatted as above and each sample is measuring the same genes with the same number of replicates per gene per sample (i.e. all genes measured must be in all samples, and each gene must have equal numbers of replicates). If you end up needing to discard replicates for certain genes/samples because they fail QC or the qPCR reaction failed, please leave the wells as just NAs instead of deleting the data. If your machine outputs non-NA values for wells where nothing was measured, please use the `readSampleSheet_NoCT` function to convert the data to NAs.
Examples of the format required:
```r
suppressPackageStartupMessages(library(WARPqpcr))
# read in the RT-qPCR data
# single replicate
rna_sampleObj <-read.csv(system.file("extdata", "samplesheet_singleRep.csv", package = "WARPqpcr"), header = TRUE, sep = "\t")
rna_sampleObj[1:10, ]
# biological replicates
rna_sampleObj <-read.csv(system.file("extdata", "samplesheet_bioReps.csv", package = "WARPqpcr"), header = TRUE, sep = "\t")
rna_sampleObj[1:12, ]
# read in ChIP-qPCR data
# single replicate
chip_sampleObj <-read.csv(system.file("extdata", "chip_qpcr_samplesheet_singleRep.csv", package = "WARPqpcr"), header = TRUE, sep = "\t")
chip_sampleObj[c(1:6, 37:42), ]
# biological replicate
chip_sampleObj <-read.csv(system.file("extdata", "chip_qpcr_samplesheet_bioReps.csv", package = "WARPqpcr"), header = TRUE, sep = "\t")
chip_sampleObj[c(1:6, 49:54), ]
Methods
The methods for biological replicates can be found in the NormqPCR documentation. In short:
- The
singleRep functions use the SD from the inital technical replicate merging to propagate error for downstream calculations.
- The
bioRep functions ignore technical replicate SD for error propagation - the calcCV function is provided to use the coefficient of variation as a filter for technical replication. The error propagation begins with calculating the mean and SD of biological replicates. In the case of RT-qPCR, the final ddCT subtraction is treated as subtraction from an arbitrary constant for error propagation.
Example for RT-qCPR single replicate data
This mode is only recommended for pilot data or cases where several constructs (shRNA, overexpression, etc.) are being screened for efficiency. No statistics are calculated because there are no biological replicates. While statistics could be computed on this data, I do not feel comfortable recommending that approach, as it is simply measuring the user's pipetting error.
suppressPackageStartupMessages(library(WARPqpcr))
# read in the qPCR data
sampleObj <- readSampleSheet(system.file("extdata", "samplesheet_singleRep.csv", package = "WARPqpcr"))
# take a look at raw values
rawct <- getRawCT(sampleObj = sampleObj)
# calculate average values and coefficient of variation (CV)
# This step is HIGHLY RECOMMENDED. The CV allows for a measure of technical replicate consistency
avgCT <- getAvgCT(sampleObj = sampleObj)
avgCT <- calcCV(avgCtObj = avgCT)
# if we want, we can make a plot of these avgCT values
plotAvgCT(avgCtObj = avgCT, theme_classic = TRUE, title = "Avg CT")
# calculate dCT values and plot them
# we can assign our HKG to a vector or pass it as an argument directly
hkg <- "HKG"
dct <- get_dCT_singleRep(sampleObj = sampleObj, hkg = hkg)
plot_dCT_singleRep(dct, theme_classic = TRUE, title = "dCT values")
# Now we can calculate ddCT values and plot -- this is typically the end result desired
# We can technically skip straight to this step, but calculating the CV first is recommended
# we need to indicate which sample is the control
control <- "NT"
ddct <- get_ddCT_singleRep(sampleObj = sampleObj, rel.exp = TRUE, hkg = hkg, control = control) # same hkg as the dCT step above
plot_ddCT_singleRep(ddct, theme_classic = TRUE, rel.exp = TRUE, title = "Relative Expression (ddCT)")
Example for RT-qPCR biological replicate data
suppressPackageStartupMessages(library(WARPqpcr))
# read in the qPCR data
sampleObj <- readSampleSheet(system.file("extdata", "samplesheet_bioReps.csv", package = "WARPqpcr"))
# check raw values
rawct <- getRawCT(sampleObj = sampleObj)
# merge technical replicates and plot
avgct <- getAvgCT(sampleObj = sampleObj)
avgct <- calcCV(avgct)
# samples have higher CVs; for the sake of example we will continue, but in real data this should be investigated
plotAvgCT(avgct, title = "Avg CT values")
# set our housekeeping gene and calculate dCT
hkg <- "HKG"
dct <- get_dCT_bioReps(sampleObj = sampleObj, hkg = hkg)
# since we have biological replicates, we can calculate significance
# stats should be performed on these dCT values
signifTest <- signifTest(dCTObj = dct, gene.name = "GeneA", var.equal = FALSE)
head(signifTest)
# now we can calculate the ddCT to get expression changes and make plots
# we will do both relative expression and log2 fold-change for the sake of demonstration
# RELATIVE EXPRESSION
relExp <- get_ddCT_bioReps(sampleObj = sampleObj, case = "KD", control = "LUC", reps.case = 3, reps.control = 3,
hkg = hkg, rel.exp = TRUE)
plot_ddCT_bioReps(ddCTobj = relExp, theme_classic = TRUE,
rel.exp = TRUE, title = "Relative Expression (ddCT)") #NB: rel.exp value must match data type
# LOG2 FOLD-CHANGE
absExp <- get_ddCT_bioReps(sampleObj = sampleObj, case = "KD", control = "LUC", reps.case = 3, reps.control = 3,
hkg = hkg, rel.exp = FALSE)
plot_ddCT_bioReps(ddCTobj = absExp, theme_classic = TRUE,
rel.exp = FALSE, title = "log2 fold-change (ddCT)") #NB: rel.exp value must match data type
Example for selecting most stable housekeeping gene
suppressPackageStartupMessages(library(WARPqpcr))
# read in the qPCR data
sampleObj <- readSampleSheet(system.file("extdata", "samplesheet_hkgStab.csv", package = "WARPqpcr"))
# get average CT values
avgCT <- getAvgCT(sampleObj = sampleObj)
# calculate stability values
hkgs <- c("gene1", "gene2", "gene3", "gene4")
hkgStab <- calcStab(avgCTobj = avgCT, hkgs = hkgs)
head(hkgStab)
Example for ChIP-qPCR single replicate data
suppressPackageStartupMessages(library(WARPqpcr))
## read in ChIP-qPCR data
sampleObj <- readSampleSheet(system.file("extdata", "chip_qpcr_samplesheet_singleRep.csv", package = "WARPqpcr"))
## analysis
# Calulcate average CTs and check CV
avgct <- getAvgCT(sampleObj = sampleObj)
avgct <- calcCV(avgct) # normally we should address values > 1, but we will skip that here
# percent input normalization
# we can set "mockName" to remove those samples from calculations if desired
dat_input <- do_chip_qpcr(sampleObj = sampleObj, method = "i", inputName = "input", inputPercent = 1,
mockName = NULL, bioReps = FALSE)
# fold enrichment
# we can set "inputName" to remove those samples from calculations if desired
dat_fe <- do_chip_qpcr(sampleObj = sampleObj, method = "fe", mockName = "mock", inputName = NULL, bioReps = FALSE)
## plots
# percent input
# we set "hideInput" to TRUE to remove those samples from the graph for visualization
# if we want to remove "mock" samples from the inputs plots, this must be done at the do_chip_qpcr step
plot_chip_qpcr(dat_input, method = "i", hideInput = TRUE, inputName = "input")
# fold enrichment
# we set "hideMock" to TRUE to remove those samples from the graph for visualization
# if we want to remove "input" samples from the fold enrichment plots, this must be done at the do_chip_qpcr step
plot_chip_qpcr(dat_fe, method = "fe", hideMock = TRUE, mockName = "mock")
Example for ChIP-qPCR biological replicate data
suppressPackageStartupMessages(library(WARPqpcr))
## read in ChIP-qPCR data
sampleObj <- readSampleSheet(system.file("extdata", "chip_qpcr_samplesheet_bioReps.csv", package = "WARPqpcr"))
## analysis
# Calulcate average CTs and check CV
avgct <- getAvgCT(sampleObj = sampleObj)
avgct <- calcCV(avgct) # normally we should address values > 1, but we will skip that here
# percent input normalization
# we can set "mockName" to remove those samples from calculations if desired
dat_input <- do_chip_qpcr(sampleObj = sampleObj, method = "i", inputName = "input", inputPercent = 1,
mockName = NULL, bioReps = TRUE)
# fold enrichment
# we can set "inputName" to remove those samples from calculations if desired
dat_fe <- do_chip_qpcr(sampleObj = sampleObj, method = "fe", mockName = "mock", inputName = NULL, bioReps = TRUE)
## plots
# percent input
# we set "hideInput" to TRUE to remove those samples from the graph for visualization
# if we want to remove "mock" samples from the inputs plots, this must be done at the do_chip_qpcr step
plot_chip_qpcr(dat_input, method = "i", hideInput = TRUE, inputName = "input")
# fold enrichment
# we set "hideMock" to TRUE to remove those samples from the graph for visualization
# if we want to remove "input" samples from the fold enrichment plots, this must be done at the do_chip_qpcr step
plot_chip_qpcr(dat_fe, method = "fe", hideMock = TRUE, mockName = "mock")
Significance testing for chip qpcr data
In this case, the gene.name argument should be the name of the region(s) of interest. The whole name of the region (e.g. factor_regionName) should be entered as it was when creating the samplesheet.
## read in ChIP-qPCR data
sampleObj <- readSampleSheet(system.file("extdata", "chip_qpcr_samplesheet_bioReps.csv", package = "WARPqpcr"))
# get dCT values
dct_values <- get_chip_dCT(sampleObj = sampleObj, inputName = "input", inputPercent = 1, method = "i")
# run t.test
signifTest <- signifTest(dCTObj = dct, gene.name = c("H3K9me3_E1", "H3K9me3_E2"), var.equal = FALSE)
References
- ReadqPCR and NormqPCR
- Selection of housekeeping genes for gene expression studies in human reticulocytes using real-time PCR
Acknowledgments
- Britany Ponvelle for designing the hex sticker!
- Archit Ghosh for providing data and advice for the ChIP-qPCR functionality!
Citation
If you like WARPqpcr, please cite it!:
Callahan SC (2020). “WARPqpcr: Web App and R Package for qPCR.” doi: 10.5281/zenodo.3686338 (URL:
http://doi.org/10.5281/zenodo.3686338).
This information can also be found by running citation(package = "WARPqpcr") in the R console.
To do
- [X] Port to Shiny App
- [X] Add vignettes/links for web app to repo
- [X] ChIP-qPCR analysis module
- [X] Add examples to README
- [X] Add ChIP-qPCR to shiny app
sccallahan/WARPqpcr documentation built on March 1, 2020, 1:23 a.m.
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knitr::opts_chunk$set( collapse = TRUE, comment = "#>", fig.path = "man/figures/README-", out.width = "100%" )
WARPqpcr
knitr::include_graphics("man/figures/WARPqpcr.png")
Web App and R Package for qPCR (WARPqpcr) provides functionality for analyzing RT-qPCR and ChIP-qPCR data and generating plots of results.
The goal of this package is to allow rapid, reproducible analysis of qPCR data, particularly in the molecular biology setting, to provide easy functions for visualizing results, and to provide a tool for selecting the best housekeeping gene from a list of candidates. Many of the functions in this package use ReadqPCR and NormqPCR packages for calculations and data structures, and the housekeeping gene stability is an implementation of an existing method (references for all of this are at the end of the README!)
Accessing the Web App
In addition to being available as an R package, WARPqpcr is available as a web application. This web app requires no knowledge of R or programming in general to use. Users only need to upload their samplesheet (format described below), choose an analysis type, then fill out a few texts fields. The analysis is automatically run, and results (.txt files with CT values, ddCT values, etc. and .png files of relative expression) are available for download as a zip file.
CLICK HERE to go to the shinyapps.io page containing the web app.
CLICK HERE for information on how to use the web application.
Installation
You can install the released version of WARPqpcr from this repo with:
# install devtools if needed -- must have for installing from github install.packages("devtools") library(devtools) # now install WARPqpcr install_github("sccallahan/WARPqpcr")
NB: Some linux systems may have difficulty installing some dependencies, particularly the rgl package (a dependency quite a way down the chain). This can be fixed by running the following lines in terminal:
``` {bash, eval=FALSE} apt-get install libx11-dev mesa-common-dev libglu1-mesa-dev
## Quick navigation * [Samplesheet format description](https://github.com/sccallahan/WARPqpcr#some-notes-about-samplesheet-format-and-methods) * [RT-qPCR single replicate](https://github.com/sccallahan/WARPqpcr#example-for-rt-qcpr-single-replicate-data) * [RT-qPCR biological replicate](https://github.com/sccallahan/WARPqpcr#example-for-rt-qpcr-biological-replicate-data) * [Housekeeping gene stability](https://github.com/sccallahan/WARPqpcr#example-for-selecting-most-stable-housekeeping-gene) * [ChIP-qPCR single replicate](https://github.com/sccallahan/WARPqpcr#example-for-chip-qpcr-single-replicate-data) * [ChIP-qPCR biological replicate](https://github.com/sccallahan/WARPqpcr#example-for-chip-qpcr-biological-replicate-data) * [References](https://github.com/sccallahan/WARPqpcr#references) * [Acknowledgements](https://github.com/sccallahan/WARPqpcr#acknowledgments) * [Citation information](https://github.com/sccallahan/WARPqpcr#citation) ## Some notes about samplesheet format and methods #### Samplesheet format and reading in data The format for the samplesheet is described in the [ReadqPCR documentation.](https://www.bioconductor.org/packages/release/bioc/vignettes/ReadqPCR/inst/doc/ReadqPCR.pdf) In short, it requires 5 columns in a *tab-delimited* file: * **Well.** The well letter/number. * **Plate.** The plate number. * **Sample.** The name of the sample being analayzed. It is *critical* that biological replicates have unique identifiers (e.g. "WT_1" and "WT_2" instead of just "WT" for both). Samples with identical names will be treated as technical replicates. * **Detector.** The gene/region being measured. In the case of ChIP-qPCR, regions should be entered as "factor_regionName" (e.g. input_R1, H3K27ac_R1, CTCF_R1, IgG_R1, etc. for each region). * **Cq.** The Ct/Cq value for the well. These values *must* be either numerics or NAs. The `readSampleSheet` function assumes that the data is formatted as above and each sample is measuring the same genes with the same number of replicates per gene per sample (i.e. all genes measured must be in all samples, and each gene must have equal numbers of replicates). If you end up needing to discard replicates for certain genes/samples because they fail QC or the qPCR reaction failed, please leave the wells as just NAs instead of deleting the data. If your machine outputs non-NA values for wells where nothing was measured, please use the `readSampleSheet_NoCT` function to convert the data to NAs. Examples of the format required: ```r suppressPackageStartupMessages(library(WARPqpcr)) # read in the RT-qPCR data # single replicate rna_sampleObj <-read.csv(system.file("extdata", "samplesheet_singleRep.csv", package = "WARPqpcr"), header = TRUE, sep = "\t") rna_sampleObj[1:10, ] # biological replicates rna_sampleObj <-read.csv(system.file("extdata", "samplesheet_bioReps.csv", package = "WARPqpcr"), header = TRUE, sep = "\t") rna_sampleObj[1:12, ] # read in ChIP-qPCR data # single replicate chip_sampleObj <-read.csv(system.file("extdata", "chip_qpcr_samplesheet_singleRep.csv", package = "WARPqpcr"), header = TRUE, sep = "\t") chip_sampleObj[c(1:6, 37:42), ] # biological replicate chip_sampleObj <-read.csv(system.file("extdata", "chip_qpcr_samplesheet_bioReps.csv", package = "WARPqpcr"), header = TRUE, sep = "\t") chip_sampleObj[c(1:6, 49:54), ]
Methods
The methods for biological replicates can be found in the NormqPCR documentation. In short:
- The
singleRepfunctions use the SD from the inital technical replicate merging to propagate error for downstream calculations. - The
bioRepfunctions ignore technical replicate SD for error propagation - thecalcCVfunction is provided to use the coefficient of variation as a filter for technical replication. The error propagation begins with calculating the mean and SD of biological replicates. In the case of RT-qPCR, the final ddCT subtraction is treated as subtraction from an arbitrary constant for error propagation.
Example for RT-qCPR single replicate data
This mode is only recommended for pilot data or cases where several constructs (shRNA, overexpression, etc.) are being screened for efficiency. No statistics are calculated because there are no biological replicates. While statistics could be computed on this data, I do not feel comfortable recommending that approach, as it is simply measuring the user's pipetting error.
suppressPackageStartupMessages(library(WARPqpcr)) # read in the qPCR data sampleObj <- readSampleSheet(system.file("extdata", "samplesheet_singleRep.csv", package = "WARPqpcr")) # take a look at raw values rawct <- getRawCT(sampleObj = sampleObj) # calculate average values and coefficient of variation (CV) # This step is HIGHLY RECOMMENDED. The CV allows for a measure of technical replicate consistency avgCT <- getAvgCT(sampleObj = sampleObj) avgCT <- calcCV(avgCtObj = avgCT) # if we want, we can make a plot of these avgCT values plotAvgCT(avgCtObj = avgCT, theme_classic = TRUE, title = "Avg CT") # calculate dCT values and plot them # we can assign our HKG to a vector or pass it as an argument directly hkg <- "HKG" dct <- get_dCT_singleRep(sampleObj = sampleObj, hkg = hkg) plot_dCT_singleRep(dct, theme_classic = TRUE, title = "dCT values") # Now we can calculate ddCT values and plot -- this is typically the end result desired # We can technically skip straight to this step, but calculating the CV first is recommended # we need to indicate which sample is the control control <- "NT" ddct <- get_ddCT_singleRep(sampleObj = sampleObj, rel.exp = TRUE, hkg = hkg, control = control) # same hkg as the dCT step above plot_ddCT_singleRep(ddct, theme_classic = TRUE, rel.exp = TRUE, title = "Relative Expression (ddCT)")
Example for RT-qPCR biological replicate data
suppressPackageStartupMessages(library(WARPqpcr)) # read in the qPCR data sampleObj <- readSampleSheet(system.file("extdata", "samplesheet_bioReps.csv", package = "WARPqpcr")) # check raw values rawct <- getRawCT(sampleObj = sampleObj) # merge technical replicates and plot avgct <- getAvgCT(sampleObj = sampleObj) avgct <- calcCV(avgct) # samples have higher CVs; for the sake of example we will continue, but in real data this should be investigated plotAvgCT(avgct, title = "Avg CT values") # set our housekeeping gene and calculate dCT hkg <- "HKG" dct <- get_dCT_bioReps(sampleObj = sampleObj, hkg = hkg) # since we have biological replicates, we can calculate significance # stats should be performed on these dCT values signifTest <- signifTest(dCTObj = dct, gene.name = "GeneA", var.equal = FALSE) head(signifTest) # now we can calculate the ddCT to get expression changes and make plots # we will do both relative expression and log2 fold-change for the sake of demonstration # RELATIVE EXPRESSION relExp <- get_ddCT_bioReps(sampleObj = sampleObj, case = "KD", control = "LUC", reps.case = 3, reps.control = 3, hkg = hkg, rel.exp = TRUE) plot_ddCT_bioReps(ddCTobj = relExp, theme_classic = TRUE, rel.exp = TRUE, title = "Relative Expression (ddCT)") #NB: rel.exp value must match data type # LOG2 FOLD-CHANGE absExp <- get_ddCT_bioReps(sampleObj = sampleObj, case = "KD", control = "LUC", reps.case = 3, reps.control = 3, hkg = hkg, rel.exp = FALSE) plot_ddCT_bioReps(ddCTobj = absExp, theme_classic = TRUE, rel.exp = FALSE, title = "log2 fold-change (ddCT)") #NB: rel.exp value must match data type
Example for selecting most stable housekeeping gene
suppressPackageStartupMessages(library(WARPqpcr)) # read in the qPCR data sampleObj <- readSampleSheet(system.file("extdata", "samplesheet_hkgStab.csv", package = "WARPqpcr")) # get average CT values avgCT <- getAvgCT(sampleObj = sampleObj) # calculate stability values hkgs <- c("gene1", "gene2", "gene3", "gene4") hkgStab <- calcStab(avgCTobj = avgCT, hkgs = hkgs) head(hkgStab)
Example for ChIP-qPCR single replicate data
suppressPackageStartupMessages(library(WARPqpcr)) ## read in ChIP-qPCR data sampleObj <- readSampleSheet(system.file("extdata", "chip_qpcr_samplesheet_singleRep.csv", package = "WARPqpcr")) ## analysis # Calulcate average CTs and check CV avgct <- getAvgCT(sampleObj = sampleObj) avgct <- calcCV(avgct) # normally we should address values > 1, but we will skip that here # percent input normalization # we can set "mockName" to remove those samples from calculations if desired dat_input <- do_chip_qpcr(sampleObj = sampleObj, method = "i", inputName = "input", inputPercent = 1, mockName = NULL, bioReps = FALSE) # fold enrichment # we can set "inputName" to remove those samples from calculations if desired dat_fe <- do_chip_qpcr(sampleObj = sampleObj, method = "fe", mockName = "mock", inputName = NULL, bioReps = FALSE) ## plots # percent input # we set "hideInput" to TRUE to remove those samples from the graph for visualization # if we want to remove "mock" samples from the inputs plots, this must be done at the do_chip_qpcr step plot_chip_qpcr(dat_input, method = "i", hideInput = TRUE, inputName = "input") # fold enrichment # we set "hideMock" to TRUE to remove those samples from the graph for visualization # if we want to remove "input" samples from the fold enrichment plots, this must be done at the do_chip_qpcr step plot_chip_qpcr(dat_fe, method = "fe", hideMock = TRUE, mockName = "mock")
Example for ChIP-qPCR biological replicate data
suppressPackageStartupMessages(library(WARPqpcr)) ## read in ChIP-qPCR data sampleObj <- readSampleSheet(system.file("extdata", "chip_qpcr_samplesheet_bioReps.csv", package = "WARPqpcr")) ## analysis # Calulcate average CTs and check CV avgct <- getAvgCT(sampleObj = sampleObj) avgct <- calcCV(avgct) # normally we should address values > 1, but we will skip that here # percent input normalization # we can set "mockName" to remove those samples from calculations if desired dat_input <- do_chip_qpcr(sampleObj = sampleObj, method = "i", inputName = "input", inputPercent = 1, mockName = NULL, bioReps = TRUE) # fold enrichment # we can set "inputName" to remove those samples from calculations if desired dat_fe <- do_chip_qpcr(sampleObj = sampleObj, method = "fe", mockName = "mock", inputName = NULL, bioReps = TRUE) ## plots # percent input # we set "hideInput" to TRUE to remove those samples from the graph for visualization # if we want to remove "mock" samples from the inputs plots, this must be done at the do_chip_qpcr step plot_chip_qpcr(dat_input, method = "i", hideInput = TRUE, inputName = "input") # fold enrichment # we set "hideMock" to TRUE to remove those samples from the graph for visualization # if we want to remove "input" samples from the fold enrichment plots, this must be done at the do_chip_qpcr step plot_chip_qpcr(dat_fe, method = "fe", hideMock = TRUE, mockName = "mock")
Significance testing for chip qpcr data
In this case, the gene.name argument should be the name of the region(s) of interest. The whole name of the region (e.g. factor_regionName) should be entered as it was when creating the samplesheet.
## read in ChIP-qPCR data sampleObj <- readSampleSheet(system.file("extdata", "chip_qpcr_samplesheet_bioReps.csv", package = "WARPqpcr")) # get dCT values dct_values <- get_chip_dCT(sampleObj = sampleObj, inputName = "input", inputPercent = 1, method = "i") # run t.test signifTest <- signifTest(dCTObj = dct, gene.name = c("H3K9me3_E1", "H3K9me3_E2"), var.equal = FALSE)
References
- ReadqPCR and NormqPCR
- Selection of housekeeping genes for gene expression studies in human reticulocytes using real-time PCR
Acknowledgments
- Britany Ponvelle for designing the hex sticker!
- Archit Ghosh for providing data and advice for the ChIP-qPCR functionality!
Citation
If you like WARPqpcr, please cite it!:
Callahan SC (2020). “WARPqpcr: Web App and R Package for qPCR.” doi: 10.5281/zenodo.3686338 (URL: http://doi.org/10.5281/zenodo.3686338).
This information can also be found by running citation(package = "WARPqpcr") in the R console.
To do
- [X] Port to Shiny App
- [X] Add vignettes/links for web app to repo
- [X] ChIP-qPCR analysis module
- [X] Add examples to README
- [X] Add ChIP-qPCR to shiny app
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