anvi-get-short-reads-from-bam

Get short reads back from a BAM file with options for compression, splitting of forward and reverse reads, etc.

🔙 To the main page of anvi’o programs and artifacts.

Authors

Can consume

profile-db contigs-db bin bam-file

Can provide

short-reads-fasta

Usage

Get short reads from a bam-file in the form of short-reads-fasta).

The purpose of this program is not to replace more efficient tools to recover short reads from BAM files such as samtool. Since it was designed to address much more subtle needs, this program may have a huge memory fingerprint for very large and numerous BAM files.

Using this program you can,

• Get all reads from one or more BAM files
• Get reads matching to contig names found in any bin in a collection
• Get reads matching to contig names found in one or more specific bins in a collection
• Get all reads matching to a specific contig name
• Get reads matching to a specific region of a specific contig name

In addition, you can use the previously-defined fetch filters via the --fetch-filter parmeter to get only short reads satisfy a particular set of criteria (i.e., those that are in forward-forward or reverse-reverse orientation, those that have a template length longer than 1,000 nucleotides, and so on). For a complete set of fetch filters you can use, please see the help menu of the program.

The program can report all reads in a single file, or you can ask reads to be split into R1 and R2 files for mapping results of paired-end sequences using the flag --split-R1-and-R2. In this case, reads that are not paired will be reported in a file with the prefix _UNPAIRED.fa.

Reads reported as a FASTA will contain necessary information in their deflines to recover which BAM file, contig, sample they are from with explicit start/stop positions on the contig to which they matched.

Getting all reads

A basic run of this program is as follows:

This will report all short reads found in BAM files BAM_FILE_1.bam and BAM_FILE_2.bam and store them into a single file. You can use as many BAM files as you wish.

Narrowing the input with anvi’o files:

You can choose to only return the short reads that are contained within a collection:

Or in a bin that is described in a collection:

Focusing on individual contigs

You can get all reads mapped to a contig:

Or define explicit start/stop positions on it:

In this mode, the program will fetch any read that includes a nucleotide that matches to anywhere in the region defined by the user. Which means, if the user sets --target-region-start to 100 and --target-region-end to 101, all reads that have a nuclotide mapping to the 100th position will be returned.

Changing the output format

You can split the output based on the directionality of paired-end reads. Adding the tag --split-R1-and-R2 causes the program to create three separate output files: one for R1 (sequences in the forward direction), one for R2 (sequences in the reverse direction; i.e. reverse complement of R1 sequences), and one for unparied reads. When doing this, you can name these three files with a prefix by using the flag -O.

You can also compress the output by adding the flag --gzip-output.

Edit this file to update this information.

Additional Resources

Are you aware of resources that may help users better understand the utility of this program? Please feel free to edit this file on GitHub. If you are not sure how to do that, find the __resources__ tag in this file to see an example.