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 (2005 success/es)
  - should not have children (2005 success/es)
  - only contains allowed attributes (2005 success/es)
a CDS feature
  - should not have children (8638 success/es)
  - appears as child of an mRNA (8638 success/es)
  - only contains allowed attributes (8638 success/es)
a gap feature
  - appears as a root node (963 success/es)
  - should not have children (963 success/es)
  - only contains allowed attributes (963 success/es)
a snoRNA feature
  - only contains allowed attributes (4 success/es)
  - should not have children (4 success/es)
  - appears as part of a gene (4 success/es)
a tRNA feature
  - only contains allowed attributes (91 success/es)
  - should not have children (91 success/es)
  - appears as part of a gene (91 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 (12 success/es)
  - should not have children (12 success/es)
  - appears as part of a gene (12 success/es)
a gene feature
  - only contains allowed attributes (8717 success/es)
  - has consistent strands across all children (8717 success/es)
  - has only allowed child types (8717 success/es)
  - appears as a root node (8717 success/es)
  - contains all child features within its coordinates (8717 success/es)
a mRNA feature
  - agrees exactly with CDS/UTR coordinates of its children (8608 success/es)
  - only contains allowed attributes (8608 success/es)
  - has a coding sequence >= 3bp (8608 success/es)
  - has at least one CDS child (8608 success/es)
  - has only allowed child types (8608 success/es)
  - has non-partial CDS ending on a stop codon (8414 success/es)
  - has non-selenocysteine CDS with no internal stop codons (8608 success/es)
  - consists of less than 50% Ns (8608 success/es)
  - appears as part of a gene (8608 success/es)
a polypeptide feature
  - agrees exactly with CDS of >=1 overlapping coding transcripts (8608 success/es)
  - only contains allowed attributes (8608 success/es)
  - has a required product attribute (8608 success/es)
  - overlaps the transcript it derives_from (8608 success/es)
  - must be derived_from a unique mRNA (8608 success/es)
  - appears as a root node (8608 success/es)

Encountered 0 parser warning/s.

Traversed 21335 CCs (10 feature types), checked 207656 nodes for 41 aspects.
Finished in 9.058969 s.