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Difficulty in using GATK for SNP and indel analysis

Hi,

I am new to Bioinformatics.I am trying to use GATK tool for finding SNP and indels but the problem is that the documentation seems to be complex for a beginner like me with so many tools to start with including IndelRealigner,MuTect,Haplotypecaller..The more I read the more confused I am getting.I also tried using Indel religner which is the first step in the process of identification of indels(correct me if wrong) but I got an error saying that you don't have the intervals file in the targetIntervals in the following command.

java -jar GenomeAnalysisTK.jar \ -T IndelRealigner \ -R reference.fasta \ -I input.bam \ -known indels.vcf \ -targetIntervals intervalListFromRTC.intervals \ -o realignedBam.bam

The error message is:Could not read file /home/aditya/Bioinfotools/gatk/intervalListFromRTC.intervals because The interval file does not exist. I don't know where to get the intervals file from.

But please guide me overall in understanding GATk.

snp indel gatk

Thanks decosterwouter and igor.I read best practices,I am getting the confidence to proceed further.

Glad to help and good luck.

Upvoting our answer will make us happy ;)

2 answers

There is a step by step guide: GATK best practices https://www.broadinstitute.org/gatk/guide/best-practices.php

Realignment is a two-step process using RealignerTargetCreator and then IndelRealigner. See detailed instructions here: https://www.broadinstitute.org/gatk/guide/article?id=38

The rest of the best practices tutorial will be helpful too.

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