This glyph has the same functionality as the Bio::Graphics::Glyph::gene glyph, but uses the
Bio::Graphics::Glyph::decorated_transcript glyph instead of the
Bio::Graphics::Glyph::processed_transcript glyph to draw transcripts.
One usecase for the 'decorated_gene' glyph is to highlight protein features of different splice forms of
the same gene to see how splice forms differ in terms of protein features, for example the presence of
predicted signal peptides or protein domains.
See Bio::Graphics::Glyph::decorated_transcript for a description of how to provide protein decorations
for transcripts.