plastid.bin.phase_by_size module

Estimate sub-codon phasing in a ribosome profiling dataset, stratified by read length.

Because ribosomes step three nucleotides in each cycle of translation elongation, in many ribosome profiling datasets a triplet periodicity is observable in the distribution of ribosome-protected footprints.

In a good dataset, 70-90% of the reads on a codon fall within the first of the three codon positions. This allows deduction of translation reading frames, if the reading frame is not known a priori. See [IGNW09] for more details.

Output files

OUTBASE_phasing.txt
Read phasing for each read length
OUTBASE_phasing.svg
Plot of phasing by read length

where OUTBASE is supplied by the user.

Note

To avoid double-counting of codons, users should either use an ROI file made by the generate subprogram of the metagene script, or supply an annotation file that includes only one transcript isoform per gene.


Command-line arguments

Positional arguments

Argument Description
roi_file Optional. ROI file of maximal spanning windows surrounding start codons, from metagene generate subprogram. Using this instead of –annotation_files prevents double-counting of codons when multiple transcript isoforms exist for a gene. See the documentation for metagene for more info about ROI files.If an ROI file is not given, supply an annotation with --annotation_files
outbase Required. Basename for output files

Optional arguments

Argument Description
-h, --help show this help message and exit
--codon_buffer  CODON_BUFFER Codons before and after start codon to ignore (Default: 5)

Warning/error options

Argument Description
-q, --quiet Suppress all warning messages. Cannot use with ‘-v’.
-v, --verbose Increase verbosity. With ‘-v’, show every warning. With ‘-vv’, turn warnings into exceptions. Cannot use with ‘-q’. (Default: show each type of warning once)

Annotation file options (one or more annotation files required)

Open one or more genome annotation files

Argument Description
--annotation_files  infile.[BED | BigBed | GTF2 | GFF3] [infile.[BED | BigBed | GTF2 | GFF3] ...] Zero or more annotation files (max 1 file if BigBed)
--annotation_format  {BED,BigBed,GTF2,GFF3} Format of annotation_files (Default: GTF2). Note: GFF3 assembly assumes SO v.2.5.2 feature ontologies, which may or may not match your specific file.
--add_three If supplied, coding regions will be extended by 3 nucleotides at their 3’ ends (except for GTF2 files that explicitly include stop_codon features). Use if your annotation file excludes stop codons from CDS.
--tabix annotation_files are tabix-compressed and indexed (Default: False). Ignored for BigBed files.
--sorted annotation_files are sorted by chromosomal position (Default: False)

Bed-specific options

Argument Description
--bed_extra_columns  BED_EXTRA_COLUMNS [BED_EXTRA_COLUMNS ...] Number of extra columns in BED file (e.g. in custom ENCODE formats) or list of names for those columns. (Default: 0).

Bigbed-specific options

Argument Description
--maxmem  MAXMEM Maximum desired memory footprint in MB to devote to BigBed/BigWig files. May be exceeded by large queries. (Default: 0, No maximum)

Gff3-specific options

Argument Description
--gff_transcript_types  GFF_TRANSCRIPT_TYPES [GFF_TRANSCRIPT_TYPES ...] GFF3 feature types to include as transcripts, even if no exons are present (for GFF3 only; default: use SO v2.5.3 specification)
--gff_exon_types  GFF_EXON_TYPES [GFF_EXON_TYPES ...] GFF3 feature types to include as exons (for GFF3 only; default: use SO v2.5.3 specification)
--gff_cds_types  GFF_CDS_TYPES [GFF_CDS_TYPES ...] GFF3 feature types to include as CDS (for GFF3 only; default: use SO v2.5.3 specification)

Count & alignment file options

Open alignment or count files and optionally set mapping rules

Argument Description
--count_files  COUNT_FILES [COUNT_FILES ...] One or more count or alignment file(s) from a single sample or set of samples to be pooled.
--countfile_format  {BAM} Format of file containing alignments or counts (Default: BAM)
--sum  SUM Sum used in normalization of counts and RPKM/RPNT calculations (Default: total mapped reads/counts in dataset)
--min_length  N Minimum read length required to be included (BAM & bowtie files only. Default: 25)
--max_length  N Maximum read length permitted to be included (BAM & bowtie files only. Default: 100)

Alignment mapping functions (bam & bowtie files only)

For BAM or bowtie files, one of the mutually exclusive read mapping functions is required:

Argument Description
--fiveprime_variable Map read alignment to a variable offset from 5’ position of read, with offset determined by read length. Requires –offset below
--fiveprime Map read alignment to 5’ position.
--threeprime Map read alignment to 3’ position
--center Subtract N positions from each end of read, and add 1/(length-N), to each remaining position, where N is specified by –nibble

Filtering and alignment mapping options

The remaining arguments are optional and affect the behavior of specific mapping functions:

Argument Description
--offset  OFFSET For –fiveprime or –threeprime, provide an integer representing the offset into the read, starting from either the 5’ or 3’ end, at which data should be plotted. For –fiveprime_variable, provide the filename of a two-column tab-delimited text file, in which first column represents read length or the special keyword ‘default’, and the second column represents the offset from the five prime end of that read length at which the read should be mapped. (Default: 0)
--nibble  N For use with –center only. nt to remove from each end of read before mapping (Default: 0)

—stylesheet {seaborn-darkgrid,seaborn-notebook,classic,seaborn-ticks,grayscale,bmh,seaborn-talk,dark_background,ggplot,fivethirtyeight,seaborn-colorblind,seaborn-deep,seaborn-whitegrid,seaborn-bright,seaborn-poster,seaborn-muted,seaborn-paper,seaborn-white,seaborn-pastel,seaborn-dark,seaborn-dark-palette}

Plotting options

Argument Description
--figformat  {eps,jpeg,jpg,pdf,pgf,png,ps,raw,rgba,svg,svgz,tif,tiff} File format for figure(s); Default: png)
--figsize  N N Figure width and height, in inches. (Default: use matplotlibrc params)
--title  TITLE Base title for plot(s).
--cmap  CMAP Matplotlib color map from which palette will be made (e.g. ‘Blues’,’autumn’,’Set1’; default: use colors from --stylesheet if given, or color cycle in matplotlibrc)
--dpi  DPI Figure resolution (Default: 150) Use this matplotlib stylesheet instead of matplotlibrc params

Script contents

plastid.bin.phase_by_size.main(argv=['-T', '-E', '-b', 'readthedocs', '-d', '_build/doctrees-readthedocs', '-D', 'language=en', '.', '_build/html'])[source]

Command-line program

Parameters:
argv : list, optional

A list of command-line arguments, which will be processed as if the script were called from the command line if main() is called directly.

Default: sys.argv[1:]. The command-line arguments, if the script is invoked from the command line

plastid.bin.phase_by_size.roi_row_to_cds(row)[source]

Helper function to extract coding portions from maximal spanning windows flanking CDS starts that are created by metagene generate subprogram.

Parameters:
row : (int, Series)

Row from a pandas.DataFrame of an ROI file made by the metagene generate subprogram

Returns:
|SegmentChain|

Coding portion of maximal spanning window