Polymorphisms are present throughout an organism's genome, and understanding which alleles are present in a particular organism's genome can be advantageous. When probing the identity of these alleles, one must minimize incorrect readings due to inefficiencies in the system. In hydrolysis probe applications, these inefficiencies may be due to over-activity of an exonuclease functionality that excises nucleotides from probes that are only partially, complementary to a region of a target. The present invention provides a mixture that contains a plurality of polymerases including one that has a 5′→3′ exonuclease functionality and one that lacks or substantially lacks it, each in a sufficient relative amount and concentration to increase efficiencies of the system.