Patent ID: 7399844

Claim:
A mixture or set of sub-mixtures comprising X-mer precursors of different length, wherein the X-mer precursors have a minimum length of 3 nucleotides; wherein the mixture has a minimum mixture coverage complexity of at least 56/N or wherein the set of sub-mixtures has a composite mixture coverage complexity of at least 56/N, wherein N represents the number of distinct X-mer precursors in the mixture; wherein each sub-mixture in said set has a reduced mixture coverage complexity as compared with the composite mixture coverage complexity; wherein each sub-mixture comprises a plurality of X-mer precursors; wherein said length is selected independently for each X-mer precursor; and wherein the mixture or set of sub-mixtures further comprises a set of tags that are distinguishable by mass spectrometry, wherein each tag is covalently linked to at least one X-mer precursor through a cleavable linker such that any given oligonucleotide sequence in the mixture is attached to a single tag with a discrete molecular weight.