makeTxDb {GenomicFeatures} | R Documentation

## Making a TxDb object from user supplied annotations

### Description

`makeTxDb` is a low-level constructor for making a TxDb object from user supplied transcript annotations.

Note that the end user will rarely need to use `makeTxDb` directly but will typically use one of the high-level constructors `makeTxDbFromUCSC`, `makeTxDbFromEnsembl`, or `makeTxDbFromGFF`.

### Usage

    makeTxDb(transcripts, splicings, genes=NULL,
             chrominfo=NULL, metadata=NULL,
             reassign.ids=FALSE, on.foreign.transcripts=c("error", "drop"))

### Arguments

`transcripts` | Data frame containing the genomic locations of a set of transcripts.
`splicings` | Data frame containing the exon and CDS locations of a set of transcripts.
`genes` | Data frame containing the genes associated to a set of transcripts.
`chrominfo` | Data frame containing information about the chromosomes hosting the set of transcripts.
`metadata` | 2-column data frame containing meta information about this set of transcripts like organism, genome, UCSC table, etc... The names of the columns must be `"name"` and `"value"` and their type must be character.
`reassign.ids` | `TRUE` or `FALSE`. Controls how internal ids should be assigned for each type of feature i.e. for transcripts, exons, and CDS. For each type, if `reassign.ids` is `FALSE` (the default) and if the ids are supplied, then they are used as the internal ids, otherwise the internal ids are assigned in a way that is compatible with the order defined by ordering the features first by chromosome, then by strand, then by start, and finally by end.
`on.foreign.transcripts` | Controls what to do when the input contains foreign transcripts i.e. transcripts that are on sequences not in `chrominfo`. If set to `"error"` (the default)

### Details

The `transcripts` (required), `splicings` (required) and `genes` (optional) arguments must be data frames that describe a set of transcripts and the genomic features related to them (exons, CDS and genes at the moment). The `chrominfo` (optional) argument must be a data frame containing chromosome information like the length of each chromosome.

`transcripts` must have 1 row per transcript and the following columns:

- `tx_id`: Transcript ID. Integer vector. No NAs. No duplicates.

- `tx_chrom`: Transcript chromosome. Character vector (or factor) with no NAs.

- `tx_strand`: Transcript strand. Character vector (or factor) with no NAs where each element is either `"+"` or `"-"`.

- `tx_start`, `tx_end`: Transcript start and end. Integer vectors with no NAs.

- `tx_name`: [optional] Transcript name. Character vector (or factor). NAs and/or duplicates are ok.

- `tx_type`: [optional] Transcript type (e.g. mRNA, ncRNA, snoRNA, etc...). Character vector (or factor). NAs and/or duplicates are ok.

- `gene_id`: [optional] Associated gene. Character vector (or factor). NAs and/or duplicates are ok.

Other columns, if any, are ignored (with a warning).

`splicings` must have N rows per transcript, where N is the nb of exons in the transcript. Each row describes an exon plus, optionally, the CDS contained in this exon. Its columns must be:

- `tx_id`: Foreign key that links each row in the `splicings` data frame to a unique row in the `transcripts` data frame. Note that more than 1 row in `splicings` can be linked to the same row in `transcripts` (many-to-one relationship). Same type as `transcripts$tx_id` (integer vector). No NAs. All the values in this column must be present in `transcripts$tx_id`.

- `exon_rank`: The rank of the exon in the transcript. Integer vector with no NAs. (`tx_id`, `exon_rank`) pairs must be unique.

- `exon_id`: [optional] Exon ID. Integer vector with no NAs.

- `exon_name`: [optional] Exon name. Character vector (or factor). NAs and/or duplicates are ok.

- `exon_chrom`: [optional] Exon chromosome. Character vector (or factor) with no NAs. If missing then `transcripts$tx_chrom` is used. If present then `exon_strand` must also be present.

- `exon_strand`: [optional] Exon strand. Character vector (or factor) with no NAs. If missing then `transcripts$tx_strand` is used and `exon_chrom` must also be missing.

- `exon_start`, `exon_end`: Exon start and end. Integer vectors with no NAs.

- `cds_id`: [optional] CDS ID. Integer vector. If present then `cds_start` and `cds_end` must also be present. NAs are allowed and must match those in `cds_start` and `cds_end`.

- `cds_name`: [optional] CDS name. Character vector (or factor). If present then `cds_start` and `cds_end` must also be present. NAs and/or duplicates are ok. Must contain NAs at least where `cds_start` and `cds_end` contain them.

- `cds_start`, `cds_end`: [optional] CDS start and end. Integer vectors. If one of the 2 columns is missing then all `cds_*` columns must be missing. NAs are allowed and must occur at the same positions in `cds_start` and `cds_end`.

- `cds_phase`: [optional] CDS phase. Integer vector. If present then `cds_start` and `cds_end` must also be present. NAs are allowed and must match those in `cds_start` and `cds_end`.

Other columns, if any, are ignored (with a warning).

`genes` should not be supplied if `transcripts` has a `gene_id` column. If supplied, it must have N rows per transcript, where N is the nb of genes linked to the transcript (N will be 1 most of the time). Its columns must be:

- `tx_id`: [optional] `genes` must have either a `tx_id` or a `tx_name` column but not both. Like `splicings$tx_id`, this is a foreign key that links each row in the `genes` data frame to a unique row in the `transcripts` data frame.

- `tx_name`: [optional] Can be used as an alternative to the `genes$tx_id` foreign key.

- `gene_id`: Gene ID. Character vector (or factor). No NAs.

Other columns, if any, are ignored (with a warning).

`chrominfo` must have 1 row per chromosome and the following columns:

- `chrom`: Chromosome name. Character vector (or factor) with no NAs and no duplicates.

- `length`: Chromosome length. Integer vector with either all NAs or no NAs.

- `is_circular`: [optional] Chromosome circularity flag. Logical vector. NAs are ok.

Other columns, if any, are ignored (with a warning).

### Value

A TxDb object.

### Author(s)

Hervé Pagès

### See Also

- `makeTxDbFromUCSC`, `makeTxDbFromBiomart`, and `makeTxDbFromEnsembl`, for making a TxDb object from online resources.

- `makeTxDbFromGRanges` and `makeTxDbFromGFF` for making a TxDb object from a GRanges object, or from a GFF or GTF file.

- The TxDb class.

- `saveDb` and `loadDb` in the AnnotationDbi package for saving and loading a TxDb object as an SQLite file.

### Examples

    transcripts <- data.frame(
                       tx_id=1:3,
                       tx_chrom="chr1",
                       tx_strand=c("-", "+", "+"),
                       tx_start=c(1, 2001, 2001),
                       tx_end=c(999, 2199, 2199))
    splicings <-  data.frame(
                       tx_id=c(1L, 2L, 2L, 2L, 3L, 3L),
                       exon_rank=c(1, 1, 2, 3, 1, 2),
                       exon_start=c(1, 2001, 2101, 2131, 2001, 2131),
                       exon_end=c(999, 2085, 2144, 2199, 2085, 2199),
                       cds_start=c(1, 2022, 2101, 2131, NA, NA),
                       cds_end=c(999, 2085, 2144, 2193, NA, NA),
                       cds_phase=c(0, 0, 2, 0, NA, NA))

    txdb <- makeTxDb(transcripts, splicings)

[Package GenomicFeatures version 1.44.2 Index]