搜索摘抄来的：
http://defindit.com/readme_files/ncbi_file_extension_format.html
For more details, contact the NCBI help desk:
info@ncbi.nlm.nih.gov
.asn genome record in asn.1 format
.faa protein sequences in fasta format, text file
.ffn protein coding portions of the genome segments
.fna genome fasta sequence
.frn rna coding portions of the genome segments
.gbk genome in genbank file format
.gff genome features
.ptt protein table
.rnt rna table
.rpt summary report
.val binary file (genome project?)
Other extensions, and my understanding of their meaning:
.gb Genbank?
.gpff Genbank protein
转播
