genotype {crlmm} | R Documentation

## Preprocessing and genotyping of Affymetrix arrays.

### Description

Preprocessing and genotyping of Affymetrix arrays.

### Usage

    genotype(filenames, cdfName, batch, mixtureSampleSize = 10^5, eps =0.1,
             verbose = TRUE, seed = 1, sns, probs = rep(1/3, 3),
             DF = 6, SNRMin = 5, recallMin = 10, recallRegMin = 1000,
             gender = NULL, returnParams = TRUE, badSNP = 0.7,  genome=c("hg19", "hg18"))

### Arguments

`filenames` | complete path to CEL files
`cdfName` | annotation package (see also `validCdfNames`)
`batch` | vector of class `character` denoting the batch for each sample in `filenames`. The `batch` vector must be the same length as the number of samples. See details.
`mixtureSampleSize` | Sample size to be use when fitting the mixture model.
`eps` | Stop criteria.
`verbose` | Logical. Whether to print descriptive messages during processing.
`seed` | Seed to be used when sampling. Useful for reproducibility
`sns` | The sample identifiers. If missing, the default sample names are `basename(filenames)`
`probs` | 'numeric' vector with priors for AA, AB and BB.
`DF` | 'integer' with number of degrees of freedom to use with t-distribution.
`SNRMin` | 'numeric' scalar defining the minimum SNR used to filter out samples.
`recallMin` | Minimum number of samples for recalibration.
`recallRegMin` | Minimum number of SNP's for regression.
`gender` | integer vector ( male = 1, female =2 ) or missing, with same length as filenames. If missing, the gender is predicted.
`returnParams` | 'logical'. Return recalibrated parameters from crlmm.
`badSNP` | 'numeric'. Threshold to flag as bad SNP (affects batchQC)
`genome` | character string indicating the UCSC genome build for the SNP annotation

### Details

For large datasets it is important to utilize the large data support by installing and loading the ff package before calling the `genotype` function. In previous versions of the `crlmm` package, we useed different functions for genotyping depending on whether the ff package is loaded, namely `genotype` and `genotype2`. The `genotype` function now handles both instances.

`genotype` is essentially a wrapper of the `crlmm` function for genotyping. Differences include (1) that the copy number probes (if present) are also quantile-normalized and (2) the class of object returned by this function, `CNSet`, is needed for subsequent copy number estimation. Note that the batch variable that must be passed to this function has no effect on the normalization or genotyping steps. Rather, `batch` is required in order to initialize a `CNSet` container with the appropriate dimensions and is used directly when estimating copy number.

### Value

A `SnpSuperSet` instance.

### Note

For large datasets, load the 'ff' package prior to genotyping – this will greatly reduce the RAM required for big jobs. See `ldPath` and `ocSamples`.

### Author(s)

R. Scharpf

### References

Carvalho B, Bengtsson H, Speed TP, Irizarry RA. Exploration, normalization, and genotype calls of high-density oligonucleotide SNP array data. Biostatistics. 2007 Apr;8(2):485-99. Epub 2006 Dec 22. PMID: 17189563.

Carvalho BS, Louis TA, Irizarry RA. Quantifying uncertainty in genotype calls. Bioinformatics. 2010 Jan 15;26(2):242-9.

### See Also

`snprma`, `crlmm`, `ocSamples`, `ldOpts`, `batch`, `crlmmCopynumber`

### Examples

    if (require(ff) & require(genomewidesnp6Crlmm) & require(hapmapsnp6)){
      ldPath(tempdir())
      path <- system.file("celFiles", package="hapmapsnp6")
      ## the filenames with full path...
      ## very useful when genotyping samples not in the working directory
      cels <- list.celfiles(path, full.names=TRUE)
      ## Note: one would need at least 10 CEL files for copy number estimation
      ## To use less RAM, specify a smaller argument to ocProbesets
      ocProbesets(50e3)
      batch <- rep("A", length(cels))
      (cnSet <- genotype(cels, cdfName="genomewidesnp6", batch=batch))

    ##Segment faults that occur with the above step can often be traced to a
    ##corrupt cel file. To check if any of the files are corrupt, try
    ##reading the files in one at a time:

    ## Not run:
    require(affyio)
    validCEL(cels)

    ## End(Not run)

      ## when gender is not specified (as in the above example), crlmm tries
      ## to predict the gender from SNPs on chromosome X
      cnSet$gender

      ## If gender is known, one should check that the assigned gender is
      ## correct. Alternatively, one can pass gender as an argument to the
      ## genotype function.
      gender <- c("female", "female", "male")
      gender[gender == "female"] <- 2
      gender[gender == "male"] <- 1
      dim(cnSet)
      table(isSnp(cnSet))
    }

[Package crlmm version 1.48.0 Index]