Methods of lowering the error rate of massively parallel DNA sequencing using duplex consensus sequencing
View Patent ↗Next Generation DNA sequencing promises to revolutionize clinical medicine and basic research. However, while this technology has the capacity to generate hundreds of billions of nucleotides of DNA sequence in a single experiment, the error rate of approximately 1% results in hundreds of millions of sequencing mistakes. These scattered errors can be tolerated in some applications but become extremely problematic when “deep sequencing” genetically heterogeneous mixtures, such as tumors or mixed microbial populations. To overcome limitations in sequencing accuracy, a method Duplex Consensus Sequencing (DCS) is provided. This approach greatly reduces errors by independently tagging and sequencing each of the two strands of a DNA duplex. As the two strands are complementary, true mutations are found at the same position in both strands. In contrast, PCR or sequencing errors will result in errors in only one strand. This method uniquely capitalizes on the redundant information stored in double-stranded DNA, thus overcoming technical limitations of prior methods utilizing data from only one of the two strands.
1. A method of preparing a sequencing library for generating sequence reads from a population of double-stranded target DNA molecules, comprising:
a) obtaining double-stranded target DNA molecules extracted from a biological sample and end-repairing double-stranded target DNA molecule fragments;
b) ligating an adapter molecule to both ends of a plurality of original double-stranded target DNA molecule fragments through enzymatic ligation, to form a population of adapter-target DNA complexes,
wherein at least a plurality of the adapter molecules each comprises:
i. a single-stranded 5′ arm, a single-stranded 3′ arm, and a single molecule identifier (SMI) sequence that alone or in combination with a sequence from the target DNA molecule fragment uniquely labels each ligated double-stranded target DNA molecule fragment such that each ligated double-stranded target DNA molecule fragment is distinguishable from other ligated double-stranded target DNA molecule fragments in the population; and
ii. a strand-distinguishing nucleotide sequence that, following the ligation step, provides a region of non-complementarity between a first strand of each adapter-target DNA complex and a second strand of the same adapter-target DNA complex; and
(c) for each of the adapter-target DNA complexes, amplifying each strand of the adapter-target DNA complex to produce a plurality of first strand adapter-target DNA complex amplicons and a plurality of second strand adapter-target DNA complex amplicons,
wherein the plurality of first strand adapter-target DNA complex amplicons are relatable to the second strand adapter-target DNA complex amplicons derived from the same original double-stranded target DNA molecule fragment by the SMI sequence alone or in combination with the sequence from the target DNA molecule fragment, and
wherein the plurality of first strand adapter-target DNA complex amplicons are distinguishable from the second strand adapter-target DNA complex amplicons derived from the same original double-stranded target DNA molecule fragment by the strand-distinguishing nucleotide sequence.
2. The method of claim 1 , wherein the extracted double-stranded adapter-target DNA molecules comprise fragments of a desired size.
3. The method of claim 1 , wherein step (a) further comprises shearing the extracted double-stranded DNA molecules to generate the double-stranded target DNA molecule fragments.
4. The method of claim 1 , wherein step (a) further comprises enzymatically cutting the extracted double-stranded DNA molecules to generate the double-stranded target DNA molecule fragments.
5. The method of claim 1 , wherein at least a plurality of the adapter-target DNA complexes comprises at least two primer binding sites.
6. The method of claim 1 , wherein the population of adapter-target DNA complexes comprise an SMI sequence in each of its strands.
7. The method of claim 1 , wherein each adapter molecule comprises a double-stranded SMI sequence, and wherein the double-stranded SMI sequence comprises (i) a first degenerate or semi-degenerate sequence and (ii) a second degenerate or semi-degenerate sequence.
8. The method of claim 7 , wherein the first and second degenerate or semi-degenerate sequences are at least partially complementary.
9. The method of claim 7 , wherein the first and second degenerate or semi-degenerate sequence comprises from 3 to 20 nucleotides.
10. The method of claim 9 , wherein the first and second degenerate or semi-degenerate sequence comprises 10 nucleotides.
11. The method of claim 1 , wherein the SMI sequence comprises a known sequence.
12. The method of claim 1 , wherein step (a) further comprises A-tailing double-stranded target DNA molecule fragments.
13. The method of claim 1 , further comprising selectively enriching target first and second strand adapter-target DNA complex amplicons by amplification of select first and second strand adapter-target DNA complexes or amplicons thereof with one or more primers that map to one or more genetic loci in a reference sequence.
14. The method of claim 1 , wherein double-stranded adapter-target DNA complexes or amplicons thereof are selectively enriched using a hybridization capture method to provide target DNA molecule fragments that map to one or more genetic loci in a reference sequence.
15. The method of claim 14 , wherein selectively enriching the double-stranded adapter-DNA molecule complexes or amplicons thereof comprises annealing adapter-target DNA strands having a desired DNA sequence by targeted hybridization to oligonucleotides with complementarity to the desired DNA sequence.
16. The method of claim 14 , wherein selectively enriching the double-stranded adapter-DNA molecule complexes or amplicons thereof comprises providing an array of capture probes, wherein a plurality of the probes in the array each hybridizes to a DNA sequence that maps to a genetic locus in the reference sequence.
17. The method of claim 1 , further comprising (d) sequencing the first and second strand adapter-target DNA complex amplicons to produce a plurality of first strand sequence reads and a plurality of second strand sequence reads.
18. The method of claim 17 , further comprising capturing target first and second strand adapter-target DNA complex amplicons using hybridization probes to provide enriched first and second strand adapter-target DNA complex amplicons, and wherein step (d) comprises sequencing the enriched first and second strand adapter-target DNA complex amplicons.