The main database divides all sequences into two groups:
Species sequences -> Species
All other sequences -> SAI ( masks, filters, profiles )
You should keep the number of SAI's small for you cannot:
search SAI's
select a subset of SAI's
IMPLEMENTED SAI's
ECOLI
A copy of the E.coli sequence. It is used to convert the absolute alignment position into an E.coli-based position and vice versa. (Note: you may use any other sequence instead of ECOLI. The name displayed in ARB_EDIT4 can be modified under Properties/NDS)