Questions tagged [variant-calling]

The process of discovering variants in individuals starting from sequencing reads. Can be subdivided into germline variant calling and somatic variant calling. Can also be used for the more specific process of finding variants starting with reads aligned to a reference genome (SAM/BAM files).

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3answers
7k views

How to subset samples from a VCF file?

I have VCF files (SNPs & indels) for WGS on 100 samples, but I want to only use a specific subset of 10 of the samples. Is there a relatively easy way to pull out only the 10 samples, while still ...
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2answers
3k views

Tools to do VCF to MAF and MAF to VCF conversion?

Normally, I would use the vcf2maf scripts to convert a VCF to a MAF (or vice versa). This is great software, but on my system, perl scripts with dependencies are easy to break. (Here it uses VEP.) ...
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91 views

How to install and use pbhoney on Mac OSX?

I download the PBSuite from SourceForge. I decompressed the file. I then moved to this directory: PBSuite_15.8.24/pbsuite/honey and typed: ...
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3answers
1k views

How can I count the number of reads that support a variant in a bam file?

I am calling variants from a human sample using bwa mem to align the reads and gatk to call the variants. I'm trying to understand why a specific variant was not called in my sample. I have checked ...
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0answers
121 views

Can Mauve export indels or is there an whole-genome aligner that can export indels?

I have aligned two whole genomes of the same species in Mauve using progressiveMauve. One of the genomes is 2 megabases longer than the other so I know it must contain some insertions. Looking at the ...
4
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1answer
197 views

Where can I get the population allele frequency vcf file?

I want to use GATK to estimate cross-sample contamination for Whole Genome Sequencing data. The specific tool is ContEst and it is run with: ...
2
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1answer
154 views

What does “motif 2 bp or longer” mean?

I'm reading a preprint on a new somatic variant discovery tool, and the first sentence of the Discussion section has me confused. Across the four datasets analyzed in this study, we discovered that ...
5
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3answers
913 views

Somatic tumor only variant calling?

I'm evaluating possibilites for somatic tumor variant calling without paired-normal samples. I'm aware of the consequences without a normal sample. All the popular variant calling tools such as ...
6
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2answers
652 views

What is indel calling and what is its purpose?

I'm having a difficulty in grasping the general purpose and concept of indel calling. What exactly is this process?
5
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1answer
419 views

Tool or script to parse annotated VCF files

I've annotated VCF files using snpEff and looking for a tool or script to parse the VCF file and clean up the file to make it interpretable for a biologist.
8
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3answers
869 views

Selecting sites from VCF which have an alt AD > 10

I have high-depth variant calling created using the HaplotypeCaller with --output_mode EMIT_ALL_SITES I'm interested in finding all sites (regardless of genotype ...
4
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2answers
474 views

Why are there missing calls in a VCF file from exome sequencing?

My data is a VCF file generated from an exome sequencing variant call pipeline. I'm not very familiar with the sequencing and variant calling process. I noticed that there are some missing genotypes, ...
6
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2answers
1k views

How do I generate a variant list (i.e. VCF file) using Illumina reads from a human genome?

This is a problem I have to solve frequently, and I'd be interested in knowing what other methods people use to solve the same problem. About twice a year, I get asked to determine variants from ...
7
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2answers
205 views

How to detect a mutation and predict its consequence?

I read a lecture notes about mutations, what kind of algorithms are there to detect mutations? How do people know if the gene is mutated or whether it's a sequencing error? I saw this which is ...
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2answers
199 views

Do variant calls change when you call from CRAM?

We're considering switching our storage format from BAM to CRAM. We work with human cancer samples, which may have very low prevalence variants (i.e. not diploid frequency). If we use lossy CRAM to ...
7
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1answer
139 views

How can I speed up INDEL calling/correction on BAM files?

The samtools mpileup command has quite a neat feature that it is able to correct mapping errors associated with misalignment of INDELs. By default, the ...
8
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4answers
873 views

Is there a point in recalibration of scores for variant calling?

The most variant calling pipeline GATK include a Base Quality Score Recalibration (BQSR) which requires a list of known variants. Recently, some work has been done for reference-free recalibration of ...
7
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2answers
235 views

variant calling on ChIP-seq style data: samtools mpileup with minimal filters

I am running samtools mpileup (v1.4) on a bam file with very choppy coverage (ChIP-seq style data). I want to get a first-pass list of positions with SNVs and their frequency as reported by the read ...
15
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2answers
359 views

How can I call structural variants (SVs) from pair-end short read resequencing data?

I have a reference genome and now I would like to call structural variants from Illumina pair-end whole genome resequencing data (insert size 700bp). There are many tools for SV calls (I made an ...
7
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3answers
2k views

How to quickly determine mutations in a read of a sam file?

After DNA sequencing, I generated a sam file through alignment of a fastq file. Before using well known variant calling programs (eg. Annovar etc.), I want to pick some reads and know what kinds of ...

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