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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32 views

Variant calling for a subset of genes using whole gneome sequencing data

I have few 100 raw fastq files from whole-genome sequencing data and I would like to map these files to a set of genes only (and not whole genome) so as to find SNP's associated with them. Can anyone ...
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23 views

Detection of CNV(InDel) of intermediate size

My impression is that small InDel (a couple of bp) is identified through cigar string in BAM and typical CNV (at least thousands of bp) is detected through read depth. What about InDel or CNV with ...
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Using BaseRecalibrator in GATK4

GATK4's BaseRecalibrator uses a list of known variants to adjust the base quality scores in a BAM file. I would like to visualize the pre and post recalibration ...
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45 views

Interpreting MultiQC plot of GATK BaseRecalibration data?

I'm using GATK4 to build a somatic variant calling pipeline. The pipeline uses MultiQC to aggregate quality control data, and one of the QC measures reported is base quality score recalibration from ...
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Helping with some definitions

In Strelka vcf in INFO column we have these ...
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40 views

NA12878 equivalent for somatic variant calling [duplicate]

I'm building a somatic variant calling pipeline with snakemake. The pipeline is hosted on Github, and I'd like to use Travis CI for continuous integration testing. ...
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42 views

Questions regarding the detection of variants (SNPs and Indels) in mammal

Greetings, I’m a newbie in bioinformatics working currently on my first project regarding detection of variants (SNPs and Indels) in mammal assembly genome. I used the following method to detect ...
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Effect size in power analysis when dealing with Poisson based variant caller

I was trying to estimate the minimum sequencing depth required to confidently detect somatic variant using Poisson distribution based variant caller (such as somatic variant caller or Pisces from ...
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How should I deal with segmental duplications when aligning NGS reads to a reference genome?

This is a follow-up of my other question. I have been having trouble calling variants in the human SMN1 and SMN2 genes, because the human genome has a large segmental duplication there and these two ...
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38 views

swap genotypes for specific fields of a vcf file

Is there a tool already established to "swap" the ref/alt information in the GT, AD and PL ...
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10 views

SnpEff gene annotation with @ such as PCDHB@

I'm using snpEff to annotate some VCFs and getting some spurious annotations that don't have transcript ids. Some of these annotations have a gene name followed by ampersand such as PCDHB@ and I'm not ...
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555 views

Find overlap between VCF files

I have two VCF files and I want to compare the missing rate in each of them, but I want to only look at sites that are present in both files. How could I go about getting a list of positions that are ...
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77 views

Why does IGV turn a VCF QUAL of “.” into -10?

IGV is turning QUAL "." into -10 from this VCF of structural variations. I'm wondering if this means anything or if I should report a bug to the IGV devs. Here's a row from a VCF: ...
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89 views

Remove variants that do not map to human genome

I received an hg38 VCF file that's had variants imputed with 1000 genomes. I've encountered some issues with the VCF; REF alleles that do not align to a reference genome, ALT alleles that do not ...
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29 views

Database for germline copy number variations in cancer

I am interested in looking at germline copy number variations in individuals that are at high risk of developing cancer. Are there any databases where I can look, if a CNV seen in our test case has ...
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35 views

Knowing which positions are variants

Let's say I'm sequencing a donor, and I have 20X coverage. And let's say all the reads covering a particular base has the same allele at the position. Then, is that position considered a "variant" ...
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157 views

Parsing .vcf file for this information

I have a .vcf file https://www.dropbox.com/s/8v73nppwg3a1tnd/LP2000109-DNA_A01_vs_LP2000103-DNA_A01.SVannotated.txt?dl=0 with this header ...
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97 views

VEP output SIFT_score unclear

We have been experimenting with VEP (Variant Effect Predictor). One of the meta data attributes that we are interested in is the SIFT score, indeed when we apply the dbNSFP plug we get a column ...
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106 views

Old versions of the reference genome and dbSNP

For benchmark purposes I’m trying to find an old version of the human reference genome (pre-GRCh37) and a matching version of dbSNP. Unfortunately it appears as though older versions of dbSNP aren’t ...
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How snippy makes MSA-like aligned fasta output from multiple samples?

From the log file it seems snippy doesn't do assembly. It only does mapping: fastq --> SAM --> BAM --> VCF --> consensus_seq/snps But if multiple ...
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Which gene I should select from this qqplot

I have a qqplot of my whole genome sequencing data; A plot is for showing possibly significant driver genes. I tried to read about qqplot though but people only say about the skewedness while I want ...
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207 views

How to correctly call a VCF file using damaged DNA? (IonTorrent & FFPE)

EDIT: I am updating this question to make it more specific to my issue. For context - original question prior to edit: How do I obtain a deamination metric when doing the variant calling using the ...
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1answer
133 views

Output from vcftools missingness

I'm new to data filtering on vcf data and vcftools. I performed variant calling on my dataset, CHR22, homo sapiens. I'd like to remove sites that are missing in more than 5% of individuals. ...
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477 views

Identifying Indels from Chromatograms

I have around 100 chromatograms (.ab1 files) from Sanger sequencing a genome at loci believed to have an indel. I'm new to interpreting this kind of data in ...
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364 views

How to run same command on multiple files?

Hi im doing Variant calling on fastq files for which i have 4000 fq files and the variant calling are done in different 9 steps. Each step generate different files that are output to next steps. So ...
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191 views

calling diploid SNVs from long reads

I'd like to call diploid SNV variants from long-reads data (~80SMRTcells PacBio). I have generated a draft reference genome for an indivudual from a heterozygous (~4%) species (Canu+Haplomerger2). ...
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IonTorrent variant caller failing, lack of ZM: tags in BAM files

I have a lot of IonTorrent sequencing data in BAM format that I want to call variants on, using the IonTorrent variant caller. However, for some of the BAM files (for about 12 samples out of ~150), ...
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646 views

No variant found using GATK 4.0 HaplotypeCaller

I am doing variant calling on RNA-seq datasets from wheat which is hexaploid,the binary alignment (BAM) files were created using STAR version 2.6.0c and variant calling was done using GATK 4.0 ...
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28 views

GRCm37-designed exon target enrichment, which reference to use?

I have exomes from 24 individual mice. The exomes are the product of Roche's SeqCap EZ HyperCap target enrichment kit. I see that the mouse exome design comes from mm9/NCBI37, the previous major ...
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886 views

Increase number of threads for GATK 4.0 HaplotypeCaller

I am using GATK version 4.0, I tried to use multiple threads for calling variants using HaplotypeCaller using following command ...
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3answers
503 views

Issues performing variant calling with GATK

I am trying to perform variant calling on a BAM file generated through STAR version STAR_2.6.0b for wheat genome using GATK haplotypecaller as follows: ...
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2k views

Why Ti/Tv ratio?

I'm interested in the transition/transversion (Ti/Tv) ratio: In substitution mutations, transitions are defined as the interchange of the purine-based A↔G or pryimidine-based C↔T. Transversions are ...
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421 views

GATK CombineVariants complains the contig order in the VCF files

I have called variants on two strains of C. elegans separately. I now want to merge the VCF files into one using the following code: Create a sequence dictionary of the reference sequence Sort the ...
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194 views

Keep Format and Individual fields when annotating VCF with VEP

I'm currently updating my Variant Calling Pipeline by switching the VCF annotating software from Annovar to VEP for a variety of regions, not least how easy it is to annotate with HGVS notation and ...
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82 views

Human SNP databases other than dbSNP

I'm working on a project to identify variants as being either germline or somatic based on nearby SNPs, and I was wondering if there were any databases of SNPs for Homo sapiens other than dbSNP? I'm ...
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697 views

Merge 2 VCFs from different variant callers

I am working with WES data for detection of somatic variants and I have used two variant callers because no variant caller is complete in itself. I have used GATK Haplotypecaller for small variants ...
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163 views

Why chose CNN for a variant caller

Google released their variant caller DeepVariant which won the highest SNP performance award in the Precision FDA Truth challenge (99.999% accuracy). From the linked github repo, we see that ...
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3k views

Converting a BAM file into VCF

I have NGS illumina RNA-seq reads from M. musculus (mm10). I am trying to find variants along the strand portion of the reads in the refseq (mm10). I mapped a pair of sequence files and generated a ...
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200 views

Books on bioinformatics algorithms

I'm looking for a book about bioinformatics algorithms, such as alignment, BLAST search, and variant calling. I'm hoping reading about this subject will give me a deeper understanding of the ...
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505 views

Can I pilon-polish long reads with Illumina short reads to improve structural variant detection?

I have pacbio Sequel data at 50 x coverage for a strain of animal. I would like to find structural variants compared to the reference genome sequence. At the moment, I align my reads to the reference ...
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1answer
233 views

Can a data file in VCF format be converted into FASTA?

I'm considering purchasing the 'MyGenome' product by Veritas Genetics to analyze my genome for a project. I'd like the data to be in FASTA format, but Veritas only provides VCF data. Is it possible to ...
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4k 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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2k 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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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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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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105 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 ...
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181 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: ...
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134 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 ...
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820 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 ...
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539 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?