We are planning a minor release of CASAVA in October that is primarily intended to handle an improvement to the number of supported index sequences. In the same release, we plan to change the default behavior and omit reads that do not pass filter from the FASTQ files. In general, we do not recommend the use of non-PF reads. Users that want to retain the non-PF reads will be able to do so by adding the following parameter to the configureBcltoFastq.pl:
--with-failed-reads
A read is classified as non-PF when more than one cycle in the first 25 cycles has a poor ratio (<0.6) of the brightest intensity to the sum of the brightest and second brightest.
Our variant calling software ignores non-PF reads, but there are many alternate methods that use all data, disregarding the non-PF flag. The inclusion of non-PF reads increases time to align, increases the data footprint, increases the measured error rate, and can lead to variant calling errors. As a result we have decided to exclude such reads as the default behavior. As a consequence of being excluded from the FASTQ files, the reads will also be excluded from all downstream processing and output including BAM files – archival and standard.
Please let me know if you have questions or concerns.
Thank you,
Semyon
--with-failed-reads
A read is classified as non-PF when more than one cycle in the first 25 cycles has a poor ratio (<0.6) of the brightest intensity to the sum of the brightest and second brightest.
Our variant calling software ignores non-PF reads, but there are many alternate methods that use all data, disregarding the non-PF flag. The inclusion of non-PF reads increases time to align, increases the data footprint, increases the measured error rate, and can lead to variant calling errors. As a result we have decided to exclude such reads as the default behavior. As a consequence of being excluded from the FASTQ files, the reads will also be excluded from all downstream processing and output including BAM files – archival and standard.
Please let me know if you have questions or concerns.
Thank you,
Semyon
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