US Patent 11884971 Compositions and techniques for nucleic acid primer extension

A method of characterizing a nucleic acid that includes steps of (a) contacting a primer-template nucleic acid hybrid with a polymerase and a mixture of nucleotides to produce an extended primer hybrid and to form a stabilized ternary complex including the extended primer hybrid, the polymerase and a nucleotide cognate of the next base in the template, wherein the mixture contains nucleotide cognates of four different base types, wherein the nucleotide cognate of the first base type has a reversible terminator, and wherein nucleotide cognates of the second, third and fourth base types are extendable; (b) detecting the stabilized ternary complex to distinguish the next base from other base types in the template; and (c) determining the presence of a base multiplet in the template nucleic acid, the base multiplet including the first base type followed by the next base.