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.