gbgb 0.1.0

Installation

pip install gbgb

Example

>>> feature
SeqFeature(FeatureLocation(ExactPosition(2931), ExactPosition(2936), strand=1), type='-10_signal')
>>> feature.qualifiers
{'ApEinfo_fwdcolor': ['pink'],
 'ApEinfo_graphicformat': ['arrow_data {{0 1 2 0 0 -1} {} 0} width 5 offset 0'],
 'ApEinfo_revcolor': ['pink'],
 'label': ['RNAII Promoter (-10 signal)']}
>>>
>>> from gbgb import convert_feature
>>> feature = convert_feature(feature)
>>> feature
SeqFeature(FeatureLocation(ExactPosition(2931), ExactPosition(2936), strand=1), type='minus_10_signal')
>>> feature.qualifiers
{'note': 'RNAII Promoter (-10 signal)'}
>>>
>>> from gbgb import genbank_feature_key
>>> genbank_feature_key('minus_10_signal')
'regulatory'

Design considerations

For the most part, Goodbye, GenBank attempts to be idempotent, i.e. features and their types/keys and qualifiers can be safely transformed any number times with the same settings. The apparent mismatch between the conversion to Sequence Ontology feature terms and valid/fixed GenBank qualifiers is to simplify downstream processing. It is up to the users which qualifiers they wish to keep, but at least the choices they are given are reasonable.

Contributing

If you have any questions or suggestions or if you have found a unique new specimen of GenBank files that you would like to convert, please open an issue.

Issues

• SO Term: “regulatory” feature type with /regulatory_class=”enhancer_blocking_element”

  There is apparently no matching Sequence Ontology term. An enhancer blocking element behaves like an insulator, but is not an insulator. It is a transcriptional cis regulatory region, but that description is too broad.

• SO Term: “misc_structure” feature type

  GenBank uses this feature type for secondary and tertiary nucleotide structures. There appears to be no matching Sequence Ontology term.

• SO Term: “assembly_gap” feature type

  GenBank has both “gap” and “assembly_gap” feature types, which appear to have slightly different meanings. However, SO only has a “gap” term, which refers to assembly gaps.

• GFF3 export

  There is no good GFF3 exporter out there, so why not write one?

  Skeleton code in gbgb.export.gff3

• Reduction of SO terms

  Allow users to specify a set of Sequence Ontology terms (inheriting from “sequence_feature”). Feature types will be reduced to the nearest Ontology term. This is to simplify downstream analysis.

• /pseudo qualifier without /pseudogene=””

  There is no matching Sequence Ontology term for this. Several GenBank files contain /pseudo without /pseudogene=”” to mean pseudogene.

• Mandatory qualifiers

  These should be filled in using a reasonable guess or errors should be thrown when trying to convert a feature without its mandatory qualifiers.

Materials

• GenBank Feature Table Definition

• GenBank Release Notes (since December 1992)

• NCBI Prokaryotic Genome Annotation Guide

• Sequence Ontology Wiki – Discontinuous Features.

  On trans-splicing.

• GFF3 Specification