makePrior {deepSNV} | R Documentation

## Compute a prior from a COSMIC VCF object

### Description

This function computes the prior probability of detecting a true variant from a variation data base. It assumes a VCF file with a CNT slot for the count of a given base substitution. Such a VCF file can be downloaded at ftp://ngs.sanger.ac.uk/production/cosmic/. The prior probability is simply defined as pi.mut * CNT[i]/sum(CNT). On sites with no count, a background probability of pi0 is used.

### Usage

    makePrior(COSMIC, regions, pi.gene = 0.1, pi.backgr = 1e-04)

### Arguments

`COSMIC` | A VCF object from COSMIC VCF export.
`regions` | A GRanges object with the regions (gene) of interest.
`pi.gene` | Probability that a gene is mutated
`pi.backgr` | Background probability of a locus being mutated. Default 1e-4, corresponding to an expected value of 1 SNV per 1e4 bases.

### Value

A vector of prior values with length given by the length of the regions GRanges object.

### Note

Experimental code, subject to changes

### Author(s)

mg14

### Examples

    ## Make prior (not run)
    #COSMIC <- readVcf("PATHTO/CosmicCodingMuts_v64_02042013_noLimit.vcf.gz", genome="GChr37")
    #prior <- makePrior(COSMIC[info(COSMIC)$GENE=="TP53"], regions=GRanges(17, IRanges(7571720,7578811)))
    #plot(prior[,1], type="h")

[Package deepSNV version 1.32.0 Index]