Nucleic acid amplification reactions suffer from the formation of off-target amplification products. This problem increases with the number of primers in the reaction, and mainly occurs because of primer-primer interactions. Thus, selectively removing hydrogen bonding units from the primer bases results in self-avoiding DNA primers that can be added to enable and improve multiplexed PCR.
As shown below, SAMRS bases, indicated with a *, can base pair with standard bases (in the target or amplicon) but not with other SAMRS bases.
Hoshika et al., 2010