Let's see if I understand what I've been looking at: 1. The .asn files contain the annotation of the genome. These point into the sequence contigs. 2. The .fa files contain the sequence contigs (FASTA format). 3. The .gbk and .gbs files contain a formated version of the .asn file with or without the sequence contigs. 4. The .mfa is a mystery! What is the .mfa file? I know it is masked FASTA format of the contigs. I'm just not sure what that means. Alex Milowski FAX: (707) 598-7649 alex at milowski.com "The excellence of grammar as a guide is proportional to the paucity of the inflexions, i.e. to the degree of analysis effected by the language considered." Bertrand Russell in a footnote of Principles of Mathematics