Method for pairwise sequencing of target polynucleotides
The invention relates to methods for pairwise sequencing of a double-stranded polynucleotide template, which methods result in the sequential determination of nucleotide sequences in two distinct and separate regions of the polynucleotide template. Using the methods of the invention it is possible to obtain two linked or paired reads of sequence information from each double-stranded template on a clustered array, rather than just a single sequencing read from one strand of the template.
1. A method of pairwise sequencing, the method comprising:
(a) providing a solid support having immobilised thereon a plurality of first template polynucleotides linked to the solid support at their 5′ ends, the solid support further comprising a plurality of 5′-end immobilized amplification primers;
(b) obtaining sequence data from a first region of the first template polynucleotides;
(c) hybridizing one or more extension oligonucleotides to the amplification primers, each extension oligonucleotide comprising a first portion complementary to an immobilized amplification primer, and a second portion whose sequence is the same sequence as a selected region of the first template polynucleotide;
(d) performing an extension reaction to extend hybridized immobilized amplification primers to produce a population of extended primers;
(e) de-hybridizing the extension oligonucleotides, hybridizing the selected regions of the templates to the extended primers and further extending the extended primers to copy the first template polynucleotides to generate a plurality of second immobilised template polynucleotides;
(f) obtaining sequence data for a second region of each of the second immobilised template polynucleotides, wherein determining the sequences of the first and second regions of the first and second template polynucleotides achieves pairwise sequencing of said first and second regions of said target polynucleotides.
2. The method of claim 1 , wherein the template polynucleotides comprise a plurality of polynucleotide duplexes immobilized on the solid support.
3. The method of claim 2 , wherein the duplexes are each formed from complementary first and second template strands linked to the solid support at or near their 5′ ends.
4. The method of claim 1 , wherein the template polynucleotides comprise a plurality of single stranded templates immobilized on the solid support.
5. The method of claim 1 , wherein the sequencing is carried out by pyrosequencing.
6. The method of claim 1 , wherein the sequencing is carried out by sequencing-by-synthesis.
7. The method of claim 1 , wherein sequencing comprises hybridizing a sequencing primer in solution to universal primer recognition regions of the target polynucleotides.
8. The method of claim 1 , wherein the sequencing comprises extension of a sequencing primer by sequential addition of labeled nucleotides.
9. The method of claim 8 , wherein the nature of the nucleotide added is determined after each of the sequential additions.
10. The method of claim 1 , wherein the amplification primers comprise a cleavage site that allows for controlled cleavage of the support-bound copies of template polynucleotides.
11. The method of claim 1 , wherein said solid support comprises beads.
12. The method of claim 11 , wherein the beads are in wells.