Sequence tags
Provided herein is a new class of nucleic acid tagging molecules which are essentially free of homopolymer stretches. The tagging molecules can tag a plurality of individual target molecules for detection with a high degree of accuracy. The tagging molecules can be used to tag at least 10 5 or 10 6 individual target molecules. The tagged individual target molecules can be subjected to high throughput sequence analysis.
1. A mixture comprising a plurality of oligonucleotides, each of said plurality of oligonucleotides comprising a degenerated sequence segment, wherein said plurality of oligonucleotides:
a. comprises at least 10 5 individual molecules;
b. does not comprise a representative with a homopolymer stretch longer than 3 nucleotide residues in the degenerated sequence segment,
wherein said degenerated sequence segment comprises one subsegment or more than one identical subsegments, wherein the subsegment has a sequence X1-X2-X3-X4, wherein X1 is a degenerated base region comprising a first set of three different bases or base analogs, X2 is a degenerated base region comprising a second set of three different bases or base analogs, X3 is a degenerated base region comprising a third set of three different bases or base analogs, and X4 is a degenerated base region comprising a fourth set of three different bases or base analogs, wherein said first, second, third and fourth sets are different from each other.
2. The mixture of claim 1 , wherein each of the plurality of oligonucleotides comprises at least 2 subsegments.
3. The mixture of claim 2 , wherein each of the plurality of oligonucleotides comprises at least 2 identical subsegments.
4. A method for tagging individual nucleic acid molecules, comprising the steps of providing a plurality of individual nucleic add molecules, adding the mixture of claim 1 , attaching one representative of said plurality of oligonucleotides to one representative each of said plurality of individual molecules.
5. The method according to claim 4 , wherein attaching comprises ligating the one representative of said plurality of oligonucleotides to the one representative of said plurality of individual molecules.
6. The method according to claim 4 , wherein said attaching comprises hybridizing a target binding site located downstream of said degenerated sequence segment to the plurality of individual molecules.
7. The method according to claim 6 , further comprising the step of elongating said plurality of individual oligonucleotides by means of performing a target dependent DNA polymerase catalyzed primer extension reaction.