Hi Abhi,

That depends on the version of the pipeline, and post-processing. I would
suggest that you check the final qualities matrix before plotting, and see
how the min and max turn out. Adjust the matrix to fit the 0-40 window,
optionally convert to called/miscalled probabilities, and plot.

Regards,
Johannes

On Mon, Aug 3, 2009 at 10:22 PM, Pratap, Abhishek <[email protected]
> wrote:

>  Thanks for a quick revert. Kind of an expected question, when you talk
> about quality format,  by default is it the Phred one ?  I will be importing
> the FASTQ from Illumina Eland output which is 0-40 scoring window.  Does
> that gets automatically converted ?
>
>
>
> Thanks,
>
> -Abhi
>
>
>
> *From:* [email protected] [mailto:[email protected]] *On
> Behalf Of *Johannes Waage
> *Sent:* Monday, August 03, 2009 4:04 PM
> *To:* Pratap, Abhishek; [email protected]
> *Subject:* Re: [Bioc-sig-seq] Calculating/plotting Avg Base Quality
>
>
>
> Try this:
>
> library(ShortRead)
> my_reads<- readFastq("~/", pattern="my_reads.fastq")
> qualities <- FastqQuality(quality(my_reads))
> qualities <- as(qualities, "matrix")
> boxplot(as.data.frame((qualities )), outline = F, xlab="Cycle",
> ylab="Quality")
>
> Depending on quality format, you might have to correct your numeric values
> in the matrix, or even convert to base call probabilities.
>
> Regards,
> Johannes Waage,
> Uni of copenhagen
>
> On Mon, Aug 3, 2009 at 9:41 PM, Pratap, Abhishek <
> [email protected]> wrote:
>
> Hi All
>
>
>
> Just wondering if there is a R function in any package to do the
> following. Want to make sure before I write something.
>
>
>
> We would like to calculate avg base quality score for each base called
> per cycle / lane.  What will be nice is to also plot these avg quality
> scores/lane  for couple of different runs.
>
>
>
> Thanks,
>
> -Abhi
>
>
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>
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