getMappedEntrezIDs: Get mapped Entrez Gene IDs from CpG probe names

In ChuanJ/test: Analysing Illumina HumanMethylation BeadChip Data

Description

Given a set of CpG probe names and optionally all the CpG sites tested, this function outputs a list containing the mapped Entrez Gene IDs as well as the numbers of probes per gene, and a vector indicating significance.

Usage

getMappedEntrezIDs(sig.cpg, all.cpg = NULL, array.type, anno = NULL)

Arguments

sig.cpg	character vector of significant CpG sites used for testing gene set enrichment
all.cpg	character vector of all CpG sites tested. Defaults to all CpG sites on the array.
array.type	the Illumina methylation array used. Options are "450K" or "EPIC".
anno	Optional. A DataFrame object containing the complete array annotation as generated by the minfi getAnnotation function. Speeds up execution, if provided.

Details

This function is used by the gene set testing functions gometh and gsameth. It maps the significant CpG probe names to Entrez Gene IDs, as well as all the CpG sites tested. It also calculates the numbers of probes for gene.

Genes associated with each CpG site are obtained from the annotation package IlluminaHumanMethylation450kanno.ilmn12.hg19 if the array type is "450K". For the EPIC array, the annotation package IlluminaHumanMethylationEPICanno.ilm10b4.hg19 is used. To use a different annotation package, please supply it using the anno argument.

Value

A list with the following elements

sig.eg	mapped Entrez Gene IDs for the significant probes
universe	mapped Entrez Gene IDs for all probes on the array, or for all the CpG probes tested.
freq	table output with numbers of probes associated with each gene
de	a vector of ones and zeroes of the same length of universe indicating which genes in the universe are significantly differentially methylated.
fract.counts	a dataframe with 2 columns corresponding to the Entrez Gene IDS for the significant probes and the associated weight to account for multi-mapping probes.

Author(s)

Belinda Phipson

See Also

gometh,gsameth

Examples

## Not run:  # to avoid timeout on Bioconductor build
library(IlluminaHumanMethylation450kanno.ilmn12.hg19)
library(org.Hs.eg.db)
library(limma)
ann <- getAnnotation(IlluminaHumanMethylation450kanno.ilmn12.hg19)

# Randomly select 1000 CpGs to be significantly differentially methylated
sigcpgs <- sample(rownames(ann),1000,replace=FALSE)

# All CpG sites tested
allcpgs <- rownames(ann)

mappedEz <- getMappedEntrezIDs(sigcpgs,allcpgs,array.type="450K")
mappedEz$sig.eg[1:10]
mappedEz$universe[1:10]
mappedEz$freq[1:10]
mappedEz$de[1:10]

## End(Not run)

ChuanJ/test documentation built on Oct. 30, 2019, 5:43 a.m.