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Importing genome into IGV.

Preparing reference file.

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In this tutorial, we're going to view the aligned reads and variants that we called in the past two lessons in the Integrated Genomics Viewer from the Broad Center. You'll need the output from Introduction to mapping (bowtie, BWA) and Introduction to variant calling (Samtools).

Getting situated

Create a fresh directory for this tutorial. We're going to assume that it's inside of the introduction_to_mapping directory, and that you have results in those subdirectories. If not, see us and we can tell you where to copy "canned" results from.

Code Block

cd $SCRATCH/intro_to_mapping

These commands copy the files we will need all into one place.

Prepare a GFF feature file for the reference sequence

IGV likes its reference genome files in GFF (Gene Feature Format). Unfortunately, our old friend bp_seqconvert.pl doesn't do GFF. Fortunately, it's cousin bp_genbank2gff3.pl does.

Code Block
module load bioperl

GFF

Code Block

bp_genbank2gff --file input.gbk --stdout > output.gff

GFF3

Code Block

cp /corral-repl/utexas/BioITeam/ngs_course/scripts/bp_genbank2gff3.pl .
./bp_genbank2gff3.pl inputNC_012967.1.gbk

Convert Genbank file to Fasta

Code Block

bp_seqconvert --from genbank --to fasta < input.gbk > output.fasta

Index Fasta file.

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Where's the output? Take a look at the *.gbk and *.gff files and try to get a handle on what is going on in this conversion.

(NB: I had to "fix" bp_genbank2gff3.pl to work on our GenBank file, by removing a line that caused an error. If someone known of an easier way to get a GFF file from a file downloaded from Genbank, please share!)

Copy files to your desktop

IGV is an interactive graphical viewer program. You can't run it on TACC, so we need to get the relevant files back to your desktop machine.

  • Indexed reference FASTA files
  • GFF reference sequence feature files
  • Sorted and indexed mapped read BAM files
  • VCF result files
Code Block
You will want the contents of these directories plus the *.gff file that we just made
You will want the contents of these directories plus the *.gff file that we just made

samtools_bowtie
comparison
NC_012967.1.gbk.gff

Import to IGV.

From the main window of IGV, click on File -> Import Genome and you should be presented with the following window.

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