idMap {EnrichmentBrowser} | R Documentation

## Mapping between gene ID types

### Description

Functionality to map between common gene ID types such as ENSEMBL and ENTREZ for gene expression datasets, gene sets, and gene regulatory networks.

### Usage

    idMap(
      obj,
      org = NA,
      from = "ENSEMBL",
      to = "ENTREZID",
      multi.to = "first",
      multi.from = "first"
    )

    idTypes(org)

### Arguments

`obj` | The object for which gene IDs should be mapped. Supported options include Gene expression dataset. An object of class `SummarizedExperiment`. Expects the names to be of gene ID type given in argument `from`. Gene sets. Either a list of gene sets (character vectors of gene IDs) or a `GeneSetCollection` storing all gene sets. Gene regulatory network. A 3-column character matrix; 1st col = IDs of regulating genes; 2nd col = IDs of regulated genes; 3rd col = regulation effect; Use '+' and '-' for activation / inhibition.
`org` | Character. Organism in KEGG three letter code, e.g. ‘hsa’ for ‘Homo sapiens’. See references.
`from` | Character. Gene ID type from which should be mapped. Corresponds to the gene ID type of argument `obj`. Defaults to `ENSEMBL`.
`to` | Character. Gene ID type to which should be mapped. Corresponds to the gene ID type the argument `obj` should be updated with. If `obj` is an expression dataset of class `SummarizedExperiment`, `to` can also be the name of a column in the `rowData` slot to specify user-defined mappings in which conflicts have been manually resolved. Defaults to `ENTREZID`.
`multi.to` | How to resolve 1:many mappings, i.e. multiple to.IDs for a single from.ID? This is passed on to the `multiVals` argument of `mapIds` and can thus take several pre-defined values, but also the form of a user-defined function. However, note that this requires that a single to.ID is returned for each from.ID. Default is `"first"`, which accordingly returns the first to.ID mapped onto the respective from.ID.
`multi.from` | How to resolve many:1 mappings, i.e. multiple from.IDs mapping to the same to.ID? Only applicable if `obj` is an expression dataset of class `SummarizedExperiment`. Pre-defined options include: 'first' (Default): returns the first from.ID for each to.ID with multiple from.IDs, 'minp': selects the from.ID with minimum p-value (according to the `rowData` column `PVAL` of `obj`), 'maxfc': selects the from.ID with maximum absolute log2 fold change (according to the `rowData` column `FC` of `obj`). Note that a user-defined function can also be supplied for custom behaviors. This will be applied for each case where there are multiple from.IDs for a single to.ID, and accordingly takes the arguments `ids` and `obj`. The argument `ids` corresponds to the multiple from.IDs from which a single ID should be chosen, e.g. via information available in argument `obj`. See examples for a case where ids are selected based on a user-defined `rowData` column.

### Details

The function 'idTypes' lists the valid values which the arguments 'from' and 'to' can take. This corresponds to the names of the available gene ID types for the mapping.

### Value

idTypes: character vector listing the available gene ID types for the mapping;

idMap: An object of the same class as the input argument `obj`, i.e. a `SummarizedExperiment` if provided an expression dataset, a list of character vectors or a `GeneSetCollection` if provided gene sets, and a character matrix if provided a gene regulatory network.

### Author(s)

Ludwig Geistlinger <Ludwig.Geistlinger@sph.cuny.edu>

### References

KEGG Organism code http://www.genome.jp/kegg/catalog/org_list.html

### See Also

`SummarizedExperiment`, `mapIds`, `keytypes`

### Examples

        # (1) ID mapping for gene expression datasets
        # create an expression dataset with 3 genes and 3 samples
        se <- makeExampleData("SE", nfeat = 3, nsmpl = 3)
        names(se) <- paste0("ENSG00000000", c("003", "005", "419"))
        idMap(se, org = "hsa")

        # user-defined mapping
        rowData(se)$MYID <- c("g1", "g1", "g2")
        idMap(se, to = "MYID")

        # data-driven resolving of many:1 mappings

        ## e.g. select from.ID with lowest p-value
        pcol <- configEBrowser("PVAL.COL")
        rowData(se)[[pcol]] <- c(0.001, 0.32, 0.15)
        idMap(se, to = "MYID", multi.from = "minp")

        ## ... or using a customized function
        maxScore <- function(ids, se)
        {
             scores <- rowData(se)[ids, "SCORE"]
             ind <- which.max(scores)
             return(ids[ind])
        }
        rowData(se)$SCORE <- c(125.7, 33.4, 58.6)
        idMap(se, to = "MYID", multi.from = maxScore)

        # (2) ID mapping for gene sets
        # create two gene sets containing 3 genes each
        s2 <- paste0("ENSG00000", c("012048", "139618", "141510"))
        gs <- list(s1 = names(se), s2 = s2)
        idMap(gs, org = "hsa", from = "ENSEMBL", to = "SYMBOL")

        # (3) ID mapping for gene regulatory networks
        grn <- cbind(FROM = gs$s1, TO = gs$s2, TYPE = rep("+", 3))
        idMap(grn, org = "hsa", from = "ENSEMBL", to = "ENTREZID")

[Package EnrichmentBrowser version 2.22.2 Index]