GFF/GTF utility providing format conversions, filtering, FASTA sequence
extraction and more.  The program gffread can be used to validate,
filter, convert and perform various other operations on GFF files.
Because the program shares the same GFF parser code with Cufflinks,
Stringtie, and gffcompare, it could be used to verify that a GFF file
from a certain annotation source is correctly "understood" by these
programs.