[Bioc-devel] Updating Rsamtools to support BAMs with >65535 CIGAR operators

[Heng Li]

Hi,

I am not sure whether I should send the request to this mailing list in this case, but I am not sure what is the best place to ask.

Anyway, an alignment with >65535 operators can't be encoded in the current BAM format. Unfortunately, a tiny fraction of ultra-long nanopore reads will be aligned with >65535 ops, which means none of the existing BAM readers works with ultra-long reads. To address this issue, we can move long CIGAR to a tag in the file and move it back in memory when the file is read.

I can update Rsamtools to support long-cigar BAMs with the approach above. The update will keep API the same but will slightly alter ABI – struct bam1_core_t in samtools/bam.c needs to be enlarged. If you think it is ok, I can generate a patch file against the git.bioconductor.org HEAD.

What do you (or the current maintainer) think? What is the best way to send this patch?

Thanks in advance,

Heng