Clarification on taxonomy fields supported for blast tab files


I want to import blasttab format files into MEGAN which have been created from megablasting against nt. They have an additional column containing taxon IDs.

The manual says, “MEGAN can also parse tabular format (BLAST output option -m 8). For this to work, the subject field must either contain taxon names or GI accession numbers. In the latter case, please use the Load GI-Lookup File button to load a GI lookup file. Alternatively, a ninth column may be supplied that contains either the taxon name or taxon Id associated with the database sequence.”

I’m confused by the reference to the ninth column. The standard blasttab format has 12 columns and the ninth is sstart. Is the manual correct, or should it say that a thirteenth column should be added?

Alternatively it sounds like I can move my taxon ID into the second column and replace the sseqid column. Is that right?

Thanks for all you do!