
List of some GFF3 files that might be useful in testing is here:
     http://www.sequenceontology.org/resources/databases.html

   
Examples found from here:
          ftp://ftp.wormbase.org/pub/wormbase/genomes/c_elegans/genome_feature_tables/GFF3/current.gff3.gz
          http://downloads.yeastgenome.org/chromosomal_feature/saccharomyces_cerevisiae.gff
          http://paramecium.cgm.cnrs-gif.fr/download/gff/parameciumDB.gff3.gz
          ftp://ftp.vectorbase.org/public_data/organism_data/agambiae/Geneset/agambiae.BASEFEATURES_PEST-AgamP3.5.gff3.gz
          ftp://ftp.vectorbase.org/public_data/organism_data/aaegypti/Geneset/aaegypti.BASEFEATURES-AaegL1.2.gff3.gz
          ftp://ftp.vectorbase.org/public_data/organism_data/cquinquefasciatus/Geneset/cquinquefasciatus.BASEFEATURES_Johannesburg-Cpip1.2.gff3.gz
          ftp://ftp.arabidopsis.org/Genes/TAIR9_genome_release/TAIR9_gff3
          ftp://ftp.sgn.cornell.edu/tomato_genome/annotation/ITAG_current/ITAG_devel_all_genomic.gff3
          ftp://ftp.sgn.cornell.edu/tomato_genome/annotation/ITAG_current/ITAG_devel_cdna_alignments.gff3
          ftp://ftp.sgn.cornell.edu/tomato_genome/annotation/ITAG_current/ITAG_devel_de_novo_gene_finders.gff3
          ftp://ftp.sgn.cornell.edu/tomato_genome/annotation/ITAG_current/ITAG_devel_gene_models.gff3
