According to the specification in /nfs/users/nfs_s/ss34/annot/skel/misc/new_gff_format.lua,

a contig feature
  - appears as a root node (20187 success/es)
  - should not have children (20187 success/es)
  - only contains allowed attributes (20187 success/es)
a CDS feature
  - should not have children (13317 success/es)
  - appears as child of an mRNA (13317 success/es)
  - only contains allowed attributes (13317 success/es)
a gap feature
  - appears as a root node (4379 success/es)
  - should not have children (4379 success/es)
  - only contains allowed attributes (4379 success/es)
a snoRNA feature
  - only contains allowed attributes (3 success/es)
  - should not have children (3 success/es)
  - appears as part of a gene (3 success/es)
a tRNA feature
  - only contains allowed attributes (72 success/es)
  - should not have children (72 success/es)
  - appears as part of a gene (72 success/es)
a snRNA feature
  - only contains allowed attributes (5 success/es)
  - should not have children (5 success/es)
  - appears as part of a gene (5 success/es)
a rRNA feature
  - only contains allowed attributes (3 success/es)
  - should not have children (3 success/es)
  - appears as part of a gene (3 success/es)
a gene feature
  - only contains allowed attributes (13311 success/es)
  - has consistent strands across all children (13311 success/es)
  - has only allowed child types (13311 success/es)
  - appears as a root node (13311 success/es)
  - contains all child features within its coordinates (13311 success/es)
a mRNA feature
  - agrees exactly with CDS/UTR coordinates of its children (13228 success/es)
  - only contains allowed attributes (13228 success/es)
  - has a coding sequence >= 3bp (13228 success/es)
  - has at least one CDS child (13228 success/es)
  - has only allowed child types (13228 success/es)
  - has non-partial CDS ending on a stop codon (12748 success/es)
  - has non-selenocysteine CDS with no internal stop codons (13227 success/es)
  - consists of less than 50% Ns (13228 success/es)
  - appears as part of a gene (13228 success/es)
a polypeptide feature
  - agrees exactly with CDS of >=1 overlapping coding transcripts (13228 success/es)
  - only contains allowed attributes (13228 success/es)
  - has a required product attribute (13228 success/es)
  - overlaps the transcript it derives_from (13228 success/es)
  - must be derived_from a unique mRNA (13228 success/es)
  - appears as a root node (13228 success/es)

Encountered 0 parser warning/s.

Traversed 66908 CCs (10 feature types), checked 378392 nodes for 41 aspects.
Finished in 10.913271 s.