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&prog; can read in and visualise BAM, VCF and BCF files. These files need
to be indexed as described below. They require &prog; to be run with at least
Java 1.6. Some examples can be found on the
<ULINK URL="http://www.sanger.ac.uk/resources/software/artemis/ngs/">Artemis homepage</ULINK>.
<ULINK URL="http://samtools.sourceforge.net/">BAM</ULINK> files need to be sorted and indexed using <ULINK
URL="http://samtools.sourceforge.net/">SAMtools</ULINK>. The index file should be in
the same directory as the BAM file. This provides an integrated
<ULINK URL="http://bamview.sourceforge.net/">BamView</ULINK> panel in &prog;, displaying
sequence alignment mappings to a reference sequence. Multiple BAM files can be loaded
in from here either by selecting each file individually or by selecting a file of
path names to the BAM files. The BAM files can be read from a local file system or remotely
from an HTTP server.
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BamView will look to match the length of the sequence in &prog; with the reference sequence lengths
in the BAM file header. It will display a warning when it opens if it finds a matching reference sequence
(from these lengths) and changes to displaying the reads for that. The reference sequence for the mapped
reads can be changed manually in the drop down list in the toolbar at the top of the BamView.
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<PARA>
In the case when the reference sequences are concatenated together into one (e.g. in a multiple
FASTA sequence) and the sequence length matches the sum of sequence lengths given in the
header of the BAM, &prog; will try to match the names (e.g. locus_tag or label) of the
features (e.g. contig or chromosome) against the reference sequence names in the BAM. It will
then adjust the read positions accordingly using the start position of the feature.
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<PARA>
When open the BamView can be configured via the popup menu which is activated by clicking on the
BamView panel. The 'View' menu allows the reads to be displayed in a number of views: stack,
strand-stack, paired-stack, inferred size and coverage.
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<PARA>
In &prog; the BamView display can be used to calculate the number of reads mapped to the
regions covered by selected features. In addition the reads per kilobase per million mapped reads (RPKM)
values for selected features can be calculated on the fly. Note this calculation can take
a while to complete.
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<PARA>
Variant Call Format (<ULINK
URL="http://1000genomes.org/wiki/doku.php?id=1000_genomes:analysis:vcf4.0">VCF</ULINK>)
files can also be read. The VCF files need to be compressed and indexed using bgzip and
tabix respectively (see the <ULINK URL="http://samtools.sourceforge.net/tabix.shtml">tabix manual</ULINK> and
<ULINK URL="http://sourceforge.net/projects/samtools/files/">download page</ULINK>).
The compressed file gets read in (e.g. file.vcf.gz) and below are the commands for
generating this from a VCF file:
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<SYNOPSIS>
bgzip file.vcf
tabix -p vcf file.vcf.gz
</SYNOPSIS>
<PARA>
Alternatively a Binary VCF (<ULINK URL="http://samtools.sourceforge.net/mpileup.shtml">BCF</ULINK>) can
be indexed with BCFtools and read into Artemis or ACT.
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<PARA>
As with reading in multiple BAM files, it is possible to read a number of (compressed and indexed)
VCF files by listing their full paths in a single file. They then get displayed in separate rows
in the VCF panel.
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<MEDIAOBJECT>
<IMAGEOBJECT>
<IMAGEDATA FORMAT="png" FILEREF="vcf.png"></IMAGEOBJECT>
</MEDIAOBJECT>
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For single base changes the colour represents the base it is being changed to, i.e. T black,
G blue, A green, C red. There are options available to filter the display by the different
types of variants. Right clicking on the VCF panel will display a pop-up menu in which
there is a 'Filter...' menu. This opens a window with check boxes for a number of varaint types and properties that can
be used to filter on. This can be used to show and hide synonymous, non-synonymous, deletion (grey),
insertion (magenta), and multiple allele (orange line with a circle at the top)
variants. In this window there is a check box to hide the variants that do not overlap CDS features.
There is an option to mark variants that introduce stop codons (into the CDS
features) with a circle in the middle of the line that represents the variant. There are also options
to filter the variants by various properties such as their quality score (QUAL) or their depth across the
samples (DP).
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<PARA>
Placing the mouse over a vertical line shows an overview of the variation as a
tooltip. Also right clicking over a line then gives an extra option in the pop-up
menu to show the details for that variation in a separate window. There are also
alternative colouring schemes. It is possible to colour the variants by whether they are
synonymous or non-synonymous or by their quality score (the lower the quality the
more faded the variant appears).
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There is an option to provide an overview of the variant types (e.g. synonymous, non-synonymous,
insertion, deletion) for selected features. Also, filtered data can be exported in VCF format, or
the reconstructed DNA sequences of variants can be exported in FASTA format for selected features or
regions for further analyses. These sequences can be used as input for multiple sequence alignment tools.