| Aggregator | - Aggregate GFF groups into composite features |
| Featname | - The name of a feature |
| Feature | - A relative segment identified by a feature type |
| Homol | - A segment of DNA that is homologous to another |
| RelSegment | - Sequence segment with relative coordinate support |
| Segment | - Simple DNA segment object |
| Typename | - The name of a feature type |