Sometimes it is necessary that a certain position in a primer is made ambiguous.
This means that the primer is actually a mix of primers, each having one of
the nucleotides defined by the ambiguity at that position. For instance, if an
´R´ is encountered in the primer sequence, this means that roughly half of the
primers in the mix will have an ´A´ at that position, and the other half a ´G´.
The ambiguity codes used in the database have been defined by the Nomenclature
Committee of the International Union of Biochemistry, and the following
symbols are used:
Document last updated: Tue Jul 15 12:00:40 MEST 2003