Linked ligation
The invention generally relates to capturing, amplifying, and sequencing nucleic acids. In certain embodiments, copies of the sense and antisense strands of a duplex template nucleic acid are captured using linked capture probes and multiple binding and extension steps to improve specificity over traditional single binding target capture techniques. Methods of seeding sequencing clusters with sense and antisense strands of a target nucleic acid are also disclosed including identifying the strands using sense-specific barcodes and confirming base calls using two sense-specific sequencing reads. Linked adapters may be used to increase adapter ligation selectively or efficiency and yield.
1. A method for of selectively ligating adapters to a target nucleic acid, the method comprising:
providing one or more 5′ linked ligation adapters each comprising (1) an adapter not complementary to the target nucleic acid and (2) a single-stranded probe complementary to a portion of the target nucleic acid,
providing one or more 3′ linked ligation adapters each comprising (1) an adapter not complementary to the target nucleic acid and (2) a single-stranded probe complementary to a portion of the target nucleic acid,
combining a sample comprising different nucleic acid sequences with the one or more 5′ linked ligation adapters and the one or more 3′ linked ligation adapters under conditions in which the one or more 5′ linked ligation adapters and the one or more 3′ linked ligation adapters hybridize specifically to at least a first fragment in the heterogeneous mixture, wherein the first fragment comprises the target nucleic acid,
ligating one of the 5′ linked ligation adapters to the 5′ terminus of the first fragment and
ligating one of the 3′ linked ligation adapters to the 3′ terminus of the first fragment, thereby producing a ligation product comprising the target nucleic acid.
2. The method of claim 1 , wherein the adapter of each of the linked ligation adapter comprises a universal priming site, a unique molecular identifier, a barcode, or any combination thereof.
3. The method of claim 1 , wherein the target nucleic acid has a length from about 100 to about 500 nucleotides.
4. The method of claim 1 , comprising combining said sample, said one or more linked ligation adapters, and a ligase under conditions in which said one or more linked ligation adapters specifically hybridize to the first fragment and said terminus of the linked ligation adapter and the terminus of the first fragment ligate together, thereby producing the ligation product.
5. The method of claim 1 , wherein said one or more linked ligation adapters comprise multiple linked ligation adapters comprising different single-stranded probes complementary to different target nucleic acid portions.
6. The method of claim 1 , wherein said one or more linked ligation adapters comprise a first linked ligation adapter comprising a first single-stranded probe complementary to a first portion of the target nucleic acid of interest and a second linked ligation adapter comprising a single-stranded probe complementary to a second portion of the target nucleic acid.
7. The method of claim 1 , wherein at least one of the one or more linked ligation adapters comprises a modified DNA base.
8. The method of claim 1 , wherein at least one of the one or more linked ligation adapters is blocked to prevent extension.
9. The method of claim 1 , wherein at least one of the one or more linked ligation adapters comprises a cleavage site.
10. The method of claim 1 , further comprising amplifying the target nucleic acid.
11. A method of enrichment of a target DNA fragment, the method comprising:
(a) producing a mixture of ligation products by combining a mixture of nucleic acid fragments with one or more 5′ linked ligation adapters and one or more 3′ linked ligation adapters of the method of claim 1 ; and
(b) removing fragments from the mixture that are not ligated to any one of the 5′ and 3′ linked ligation adapters.