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 (1667 success/es)
  - should not have children (1667 success/es)
  - only contains allowed attributes (1667 success/es)
a CDS feature
  - should not have children (9060 success/es)
  - appears as child of an mRNA (9060 success/es)
  - only contains allowed attributes (9060 success/es)
a gap feature
  - appears as a root node (817 success/es)
  - should not have children (817 success/es)
  - only contains allowed attributes (817 success/es)
a snoRNA feature
  - only contains allowed attributes (16 success/es)
  - should not have children (16 success/es)
  - appears as part of a gene (16 success/es)
a tRNA feature
  - only contains allowed attributes (95 success/es)
  - should not have children (95 success/es)
  - appears as part of a gene (95 success/es)
a snRNA feature
  - only contains allowed attributes (2 success/es)
  - should not have children (2 success/es)
  - appears as part of a gene (2 success/es)
a rRNA feature
  - only contains allowed attributes (17 success/es)
  - should not have children (17 success/es)
  - appears as part of a gene (17 success/es)
a gene feature
  - only contains allowed attributes (9101 success/es)
  - has consistent strands across all children (9101 success/es)
  - has only allowed child types (9101 success/es)
  - appears as a root node (9101 success/es)
  - contains all child features within its coordinates (9101 success/es)
a mRNA feature
  - agrees exactly with CDS/UTR coordinates of its children (8971 success/es)
  - only contains allowed attributes (8971 success/es)
  - has a coding sequence >= 3bp (8971 success/es)
  - has at least one CDS child (8971 success/es)
  - has only allowed child types (8971 success/es)
  - has non-partial CDS ending on a stop codon (8751 success/es)
  - has non-selenocysteine CDS with no internal stop codons (8971 success/es)
  - consists of less than 50% Ns (8971 success/es)
  - appears as part of a gene (8971 success/es)
a polypeptide feature
  - agrees exactly with CDS of >=1 overlapping coding transcripts (8971 success/es)
  - only contains allowed attributes (8971 success/es)
  - has a required product attribute (8971 success/es)
  - overlaps the transcript it derives_from (8971 success/es)
  - must be derived_from a unique mRNA (8971 success/es)
  - appears as a root node (8971 success/es)

Encountered 0 parser warning/s.

Traversed 21406 CCs (10 feature types), checked 214872 nodes for 41 aspects.
Finished in 8.755247 s.