Complexity management of genomic DNA
View Patent ↗The presently claimed invention provides for novel methods and kits for reducing the complexity of a nucleic acid sample by providing non-gel based methods for amplification of a subset of the sequences in a sample. In a preferred embodiment, amplification of a subset can be accomplished by digesting a sample with two or more restriction enzymes and ligating adaptors to the fragments so that only a subset of the fragments can be amplified. The invention further provides for analysis of the above amplified sample by hybridization to an array, which may be specifically designed to interrogate the desired fragments for particular characteristics, such as, for example, the presence or absence of a polymorphism.
1. A method for analyzing a nucleic acid sample comprising:
fragmenting the nucleic acid sample using a first and a second restriction enzyme to produce fragments;
ligating a first and a second adaptor to the fragments to produce adaptor-ligated fragments, wherein the first adaptor is blocked from ligation to the fragments at the 3′ end of one strand of the first adaptor, and the second adaptor is blocked from ligation to the fragments at the 5′ end of one strand of the second adaptor and wherein the first adaptor ligates to the fragments cut by the first restriction enzyme and the second adaptor ligates to the fragments cut by the second restriction enzyme;
amplifying the adaptor-ligated fragments to produce amplified fragments, wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor are enriched in the amplified fragments relative to the adaptor-ligated fragments that contain the first adaptor and do not contain the second adaptor, and to the adaptor-ligated fragments that contain the second adaptor and do not contain the first adaptor;
providing a nucleic acid array consisting essentially of probes designed to detect the bases present at a plurality of polymorphisms predicted to be present in the amplified fragments;
hybridizing the amplified fragments to the array; and
analyzing a hybridization pattern resulting from the hybridization.
2. The method of claim 1 wherein the polymorphisms are single nucleotide polymorphisms (SNPs).
3. The method of claim 1 wherein the polymorphisms predicted to be present in the amplified fragments are first determined by a computer system.
4. The method of claim 1 wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor comprise at least 0.01% of the nucleic acid sample.
5. The method of claim 1 wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor comprise at least 0.05% of the nucleic acid sample.
6. The method of claim 1 wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor comprise at least 3% of the nucleic acid sample.
7. The method of claim 1 wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor comprise at least 12% of the nucleic acid sample.
8. The method of claim 1 wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor comprise at least 30% of the nucleic acid sample.
9. The method of claim 1 wherein the nucleic acid sample is genomic DNA, DNA, or double stranded cDNA derived from RNA, total RNA or mRNA.
10. The method of claim 1 wherein ligation is blocked by introducing a gap of at least one nucleotide between one strand of the first or the second adaptor and one stand of each of the fragments produced by fragmenting with the first and the second restriction enzyme.
11. The method of claim 1 wherein ligation of the second adaptor is blocked by the absence of a phosphate at the 5′ end of an adaptor strand of the second adaptor.
12. The method of claim 1 wherein ligation is blocked by the presence of a modified nucleotide at the 5′ end of an adaptor strand of the second adaptor and 3′ end of an adaptor strand of the first adaptor end of an adaptor strand.
13. The method of claim 1 wherein ligation is blocked by a terminal modification in one strand of the first and second adaptor.
14. A method of determining the base present at a polymorphism in an individual comprising:
providing a nucleic acid sample from the individual;
fragmenting the nucleic acid sample using a first and a second restriction enzyme to produce fragments wherein the polymorphism is predicted to be on a fragment that is cut on one end by the first restriction enzyme and on the other end by the second restriction enzyme;
ligating a first and a second adaptor to the fragments to produce adaptor-ligated fragments, wherein the first adaptor is blocked from ligation to the fragments at the 3′ end of one strand of the first adaptor, and the second adaptor is blocked from ligation to the fragments at the 5′ end of one strand of the second adaptor and wherein the first adaptor ligates to the fragments cut by the first restriction enzyme and the second adaptor ligates to the fragments cut by the second restriction enzyme; and
amplifying the adaptor-ligated fragments to produce amplified fragments, wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor are enriched in the amplified fragments relative to the adaptor-ligated fragments that contain the first adaptor and do not contain the second adaptor, and to the adaptor-ligated fragments that contain the second adaptor and do not contain the first adaptor;
providing a nucleic acid array consisting essentially of probes designed to detect the bases present at a plurality of polymorphisms predicted to be present in the amplified fragments;
hybridizing the amplified fragments to the array;
generating a hybridization pattern resulting from the hybridization; and
determining the base present at the polymorphism in the individual based upon an analysis of the hybridization pattern.
15. The method of claim 14 wherein the polymorphism is a single nucleotide polymorphism (SNP).
16. The method of claim 15 wherein the SNP is associated with a disease.
17. The method of claim 15 wherein the SNP is associated with the efficacy of a drug.
18. A method of determining the base present at a nucleotide polymorphism in a population of individuals comprising:
providing a first nucleic acid sample from each of the individuals;
providing a second nucleic acid samples by:
fragmenting the first nucleic acid sample using a first and a second restriction enzyme to produce fragments wherein the polymorphism is predicted to be on a fragment that is cut on one end by the first restriction enzyme and on the other end by the second restriction enzyme;
ligating a first and a second adaptor to the fragments to produce adaptor-ligated fragments, wherein the first adaptor is blocked from ligation to the fragments at the 3′ end of one strand of the first adaptor, and the second adaptor is blocked from ligation to the fragments at the 5′ end of one strand of the second adaptor and wherein the first adaptor ligates to the fragments cut by the first restriction enzyme and the second adaptor ligates to the fragments cut by the second restriction enzyme; and
amplifying the adaptor-ligated fragments to produce the second nucleic acid samples, wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor are enriched in the second nucleic acid samples relative to the adaptor-ligated fragments that contain the first adaptor and do not contain the second adaptor, and to the adaptor-ligated fragments that contain the second adaptor and do not contain the first adaptor;
providing a plurality of identical nucleic acid arrays consisting essentially of probes designed to detect the bases present at a plurality of polymorphisms predicted to be present in the second nucleic acid samples;
hybridizing each of the second nucleic acid samples to one of the plurality of identical nucleic acid arrays;
generating a plurality of hybridization patterns resulting from the hybridizations; and
analyzing the hybridization patterns to determine the bases present at the polymorphism in the population of individuals.
19. The method of claim 18 , wherein the polymorphism is a single nucleotide polymorphism (SNP).
20. The method of claim 19 wherein the SNP is associated with a disease.
21. The method of claim 19 wherein the SNP is associated with the efficacy of a drug.
22. A method for genotyping an individual comprising:
providing a first nucleic sample from the individual;
providing second nucleic acid samples by:
fragmenting the first nucleic acid sample using a first and a second restriction enzyme to produce fragments wherein a collection of polymorphisms is predicted to be present in the fragments cut on one end by the first restriction enzyme and on the other end by the second restriction enzyme;
ligating a first and a second adaptor to the fragments to produce adaptor-ligated fragments, wherein the first adaptor is blocked from ligation to the fragments at the 3′ end of one strand of the first adaptor, and the second adaptor is blocked from ligation to the fragments at the 5′ end of one strand of the second adaptor and wherein the first adaptor ligates to the fragments cut by the first restriction enzyme and the second adapter ligates to the fragments cut by the second restriction enzyme; and
amplifying the adaptor-ligated fragments to produce the second nucleic acid samples, wherein the adaptor-ligated fragments that contain both the first adaptor and the second adaptor are enriched in the second nucleic acid samples relative to the adaptor-ligated fragments that contain the first adaptor and do not contain the second adaptor, and to the adaptor-ligated fragments that contain the second adaptor and do not contain the first adaptor;
providing a plurality of identical nucleic acid arrays consisting essentially of probes designed to detect the bases present at a plurality of polymorphisms predicted to be present in the second nucleic acid samples hybridizing each of the second nucleic acid samples to one of the plurality of identical nucleic acid arrays;
generating a hybridization pattern resulting from the hybridizations; and
determining the bases present at one or more polymorphisms thereby genotyping the individual present in the collection of polymorphisms.