GlfTrio

glfTrio is a GLF-based variant caller for next-generation sequencing data. It takes three GLF format genotype likelihood files as input and generates a VCF-format set of variant calls as output.

Basic Usage Example

Here is an example of how glfTrio works:

  glfSingle -g NA19240.chrom20.SLX.glf -b NA19240.chrom20.SLX.vcf > NA19240.chrom20.SLX.log

Command Line Options

Input Files

 -f genotype likelihood file    Father's GLF-format genotype likelihood file
 -m genotype likelihood file    Mother's GLF-format genotype likelihood file
 -c genotype likelihood file    Child's GLF-format genotype likelihood file

Basic Output Options

 -b base call file              Specifies the name of the output VCF-format base call file
 -p threshold                   The threshold for base calling. Base calls will be made when their posterior likelihood exceeds threshold
 --reference                        Positions called as homozygous reference will be included in the output.  
 --verbose                          Print debug information to the screen

Filtering According to Depth and Map Quality

 --minMapQuality threshold      Positions where the root-means squared mapping quality falls below this threshold will be excluded.
 --strict                           When the map quality is interpreted strictly, all three trio individuals must exceed minMapQuality 
                                    before a call is made. Without the --strict option, reads for individuals below the threshold are ignored.

 --minDepth      threshold      Positions where the read depth falls below this threshold will be excluded.
 --maxDepth      threshold      Positions where the read depth exceeds this threshold will be excluded.

Sample Labels

 --father father label          Specifies a label for the male parent, which will be included in the output VCF file
 --mother mother label          Specifies a label for the female parent, which will be included in the output VCF file
 --child child label            Specifies a label for the child, which will be included in the output VCF file

X Chromosome Variant Calling

 --xChr chromosome name         Label for the 'X' chromosome in the GLF file
 --xStart sex chromosome start  Start of the non-pseudo-autosomal portion of the X (2,709,521 bp in build 36)
 --xStop sex chromosome end     End of the non-pseudo-autosomal portion of the X (154,584,237 bp in build 36)

TODO

When calling genotypes on the X chromosome, glfTrio should properly account for male offspring. Currently, it assumes the offspring are female ... because the offspring for the two deeply sequenced 1000 Genomes trios are both female.