plinkUtils {GWASTools} | R Documentation

## Utilities to create and check PLINK files

### Description

`plinkWrite` creates ped and map format files (used by PLINK) from a `GenotypeData` object. `plinkCheck` checks whether a set of ped and map files has identical data to a `GenotypeData` object.

### Usage

    plinkWrite(genoData, pedFile="testPlink", family.col="family",
      individual.col="scanID", father.col="father", mother.col="mother",
      phenotype.col=NULL,
      rs.col="rsID", mapdist.col=NULL, scan.exclude=NULL,
      scan.chromosome.filter=NULL, blockSize=100, verbose=TRUE)

    plinkCheck(genoData, pedFile, logFile="plinkCheck.txt", family.col="family",
      individual.col="scanID", father.col="father", mother.col="mother",
      phenotype.col=NULL,
      rs.col="rsID", map.alt=NULL, check.parents=TRUE, check.sex=TRUE,
      scan.exclude=NULL, scan.chromosome.filter=NULL, verbose=TRUE)

### Arguments

`genoData` | A `GenotypeData` object with scan and SNP annotation.
`pedFile` | prefix for PLINK files (pedFile.ped, pedFile.map)
`logFile` | Name of the output file to log the results of `plinkCheck`
`family.col` | name of the column in the scan annotation that contains family ID of the sample
`individual.col` | name of the column in the scan annotation that contains individual ID of the sample
`father.col` | name of the column in the scan annotation that contains father ID of the sample
`mother.col` | name of the column in the scan annotation that contains mother ID of the sample
`phenotype.col` | name of the column in the scan annotation that contains phenotype variable (e.g. case control statue) of the sample
`rs.col` | name of the column in the SNP annotation that contains rs ID (or some other ID) for the SNP
`mapdist.col` | name of the column in the SNP annotation that contains genetic distance in Morgans for the SNP
`map.alt` | data frame with alternate SNP mapping for genoData to PLINK. If not `NULL`, this annotation will be used to compare SNP information to the PLINK file, rather than the default conversion from the SNP annotation embedded in `genoData`. Columns should include "snpID", "rsID", "chromosome", "position".
`check.parents` | logical for whether to check the father and mother columns
`check.sex` | logical for whether to check the sex column
`scan.exclude` | vector of scanIDs to exclude from PLINK file
`scan.chromosome.filter` | a logical matrix that can be used to zero out (set to missing) some chromosomes, some scans, or some specific scan-chromosome pairs. Entries should be `TRUE` if that scan-chromosome pair should have data in the PLINK file, `FALSE` if not. The number of rows must be equal to the number of scans in `genoData`. The column labels must be in the set ("1":"22", "X", "XY", "Y", "M", "U").
`blockSize` | Number of samples to read from `genoData` at a time
`verbose` | logical for whether to show progress information.

### Details

If "alleleA" and "alleleB" columns are not found in the SNP annotation of `genoData`, genotypes are written as "A A", "A B", "B B" (or "0 0" for missing data).

If `phenotype.col=NULL`, `plinkWrite` will use "-9" for writing phenotype data and `plinkCheck` will omit checking this column.

If `mapdist.col=NULL`, `plinkWrite` will use "0" for writing this column in the map file and `plinkCheck` will omit checking this column.

`plinkCheck` first reads the map file and checks for SNP mismatches (chromosome, rsID, and/or position). Any mismatches are written to `logFile`. `plinkCheck` then reads the ped file line by line, recording all mismatches in `logFile`. SNPs and sample order is not required to be the same as in `genoData`. In the case of genotype mismatches, for each sample the log file output gives the position of the first mismatched SNP in the PLINK file, as well as the genotypes of the first six mismatched SNPs (which may not be consecutive).

These utilities convert between chromosome coding in `GenotypeData`, which by default is 24=XY, 25=Y, and PLINK chromosome coding, which is 24=Y, 25=XY.

Larger blockSize will improve speed but will require more RAM.

### Value

`plinkCheck` returns `TRUE` if the PLINK files contain identical data to `genoData`, and `FALSE` if a mismatch is encountered.

### Author(s)

Stephanie Gogarten, Tushar Bhangale

### References

Please see http://pngu.mgh.harvard.edu/~purcell/plink/data.shtml#ped for more information on the ped and map files.

### See Also

`snpgdsBED2GDS`

### Examples

    library(GWASdata)
    ncfile <- system.file("extdata", "illumina_geno.nc", package="GWASdata")
    data(illuminaSnpADF, illuminaScanADF)
    genoData <- GenotypeData(NcdfGenotypeReader(ncfile),
      scanAnnot=illuminaScanADF, snpAnnot=illuminaSnpADF)

    pedfile <- tempfile()
    plinkWrite(genoData, pedfile)
    logfile <- tempfile()
    plinkCheck(genoData, pedfile, logfile)

    # exclude samples
    plinkWrite(genoData, pedfile, scan.exclude=c(281, 283),
      blockSize=10)
    plinkCheck(genoData, pedfile, logfile)
    readLines(logfile)
    #samples not found in Ped:
    #281
    #283

    close(genoData)
    unlink(c(logfile, paste(pedfile, "*", sep=".")))

[Package GWASTools version 1.38.0 Index]