Linked target capture
The invention generally relates to sequencing library preparation methods. In certain embodiments, two or more template nucleic acids are joined together by a linking molecule, such as a PEG derivative. Identical copies of a nucleic acid fragment or both strands of a duplex fragment may be linked together. The linked nucleic acids are amplified, creating linked amplicons. Emulsion PCR with linked primers creates linked template nucleic acids for seeding sequencing clusters and errors can be readily identified by their presence on only one of the linked fragments.
1. A method of preparing a sequencing library, the method comprising:
using a plurality of amplification primers joined with a linker;
forming a partition including a nucleic acid fragment, the linked plurality of amplification primers, and amplification primers;
amplifying the nucleic acid fragment in the partition, thereby creating a complex comprising joined copies of the nucleic acid fragment;
performing a sequencing reaction with the complex to determine a sequence of a target; and
identifying a base at one position in the target as a true variant based on a signal from the sequence reaction and identifying an error when the signal indicates that bases at corresponding second positions in the complex are not the same.
2. The method of claim 1 , wherein the complex includes copies of a sense strand of the target and copies of an antisense strand of the target.
3. The method of claim 1 , wherein the partition uses one selected from the group consisting of emulsions, droplets, and wells.
4. The method of claim 1 , wherein the amplification primers include a first primer linked to a second primer via a solid support.
5. The method of claim 4 , wherein the solid support is selected from the group consisting of a microbead, a bead, a channel wall, a microchip, and a surface.
6. The method of claim 4 , wherein extending the first and second primers produces copies of sense and anti-sense strands of the target.
7. The method of claim 6 , wherein the nucleic acid fragment includes one or more adaptors that have been ligated to the target, wherein the adaptors include sense-specific barcodes that are used to confirm the presence of both sense and anti-sense strands in the sequencing reaction.
8. The method of claim 1 , wherein the linked plurality of amplification primers are universal amplification primers.
9. The method of claim 8 , further comprising, prior to the amplifying step, ligating an adapter to the nucleic acid fragment, said adapter comprising a universal priming site corresponding to the universal amplification primers.
10. The method of claim 9 , wherein the adapter further comprises a cluster identification sequence.
11. The method of claim 1 , wherein the joined copies of the nucleic acid fragment form a seed for a single sequencing reaction on a flow cell.
12. The method of claim 1 , wherein the joined copies of the nucleic acid fragment are identical and linked to each other in phase to prevent binding therebetween.
13. The method of claim 12 , wherein the complex comprises amplification products attached to beads.
14. The method of claim 1 , wherein a partition comprises a droplet of an emulsion and the amplification products are linked to beads and the method further comprises breaking the emulsion and loading the amplification products onto a flow cell of a sequencing instrument.
15. The method of claim 1 , wherein the sequencing reaction incorporates fluorescently-labeled nucleotides into copies of the amplification products.
16. The method of claim 15 , wherein a position in the amplification products that was amplified without error generates fluorescence that is the same among products of the sequencing reaction.
17. The method of claim 15 , wherein a position in the amplification products that was amplified with polymerase error generates fluorescence that is not the same among products of the sequencing reaction.