Pysam is a python module for reading and manipulating files in the
SAM/BAM format. The SAM/BAM format is a way to store efficiently large
numbers of alignments (Li 2009), such as those routinely created by
next-generation sequencing methods.

Pysam is a lightweight wrapper of the samtools_ C-API. Pysam also
includes an interface for tabix.

Reference: Li et al. Bioinformatics. 2009 Aug 15;25(16):2078-9.
doi: 10.1093/bioinformatics/btp352.
The Sequence Alignment/Map format and SAMtools.