plotExpr {doseR} | R Documentation

## plotExpr Function to generate a boxplot (expression) for a SummarizedExperiment object based on the replicate data.

### Description

This function generates a boxplot of FPKM expression values from the supplied object. FPKM values are averaged across replicates and partitioned among groups of loci as specified in a selected column from the annotation slot of the provided object.

### Usage

    plotExpr(se, groupings= NULL, mode_mean=TRUE,
    treatment=levels(colData(se)$Treatment),
    LOG2=TRUE, clusterby_grouping=TRUE, ...)

### Arguments

`se` | A SummarizedExp object containing FPKM values and at least one annotation column.
`groupings` | Specifies which column in the dataframe of the annotation slot that will be used to group loci in the boxplot. Can provide either a character value matching the column name, or a single numerical value used as an index of dataframe columns.
`mode_mean` | Logical. If TRUE then FPKM values are averaged by mean across replicates within treatment. If FALSE, values are averaged by median.
`treatment` | A character vector indicating which treatments (i.e. levels in the replicates slot vector) will be plotted. Order matters, and controls the ordering of treatments represented in the boxplot.
`LOG2` | Logical. If TRUE then average FPKM values are Log2 transformed.
`clusterby_grouping` | Logical. If TRUE then boxplots are arranged by locus annotation grouping. If FALSE they are arranged by treatment levels, as indicated in the treatment argument.
`...` | Additional named arguments and graphical parameters passed to the boxplot function.

### Details

This function generates boxplots to visualize the distribution of FPKM expression values provided in an object, arranged by selected treatments and locus annotations. FPKM values are averaged (mean or median) within selected treatments, to provide a single expression value per locus per treatment. Loci are partitioned into groupings based on a specified column in the dataframe of annotations slot of the object. Thus a box is drawn for each grouping of loci for each treatment indicated. Desired treatments and their ordering are specified by the treatment argument. Groupings are arranged by sort order of the annotation column indicated, and can thus be controlled by providing a factor with a pre-specified level order. By default (clusterby_grouping = TRUE), boxes are arranged by annotation group first, and then by treatment, but setting this option to FALSE arranges boxes by treatment and then annotation group. This function uses the base graphics boxplot function to generate the plot, so can accept all relevant graphical arguments for customizing the figure; see boxplot for details.

### Value

Returns an invisible data frame containing values and labels used to generate the figure.

### Author(s)

AJ Vaestermark, JR Walters.

### References

The 'doseR' package, 2018 (in press).

### Examples

    data(hmel.se)
    plotExpr(se, groupings = "annotation.ZA", treatment = 'Male' )

[Package doseR version 1.8.0 Index]