Quantification of a minority nucleic acid species
First Claim
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1. A method for determining the amount of a minority nucleic acid species in a sample comprising:
- (a) contacting under amplification conditions a nucleic acid sample comprising a minority species and a majority species, the combination of the minority species and the majority species comprising total nucleic acid in the sample, with;
(i) a first set of amplification primers that specifically amplify a first region in sample nucleic acid comprising a feature that (1) is present in the minority nucleic acid species and is not present in the majority nucleic acid species, or (2) is not present in the minority nucleic acid species and is present in the majority nucleic acid species,(ii) a second set of amplification primers that amplify a second region in the sample nucleic acid allowing for a determination of total nucleic acid in the sample, wherein the first region and the second region are different, and(iii) one or more inhibitory oligonucleotides, each comprising a nucleotide sequence complementary to a nucleotide sequence in the second region, wherein the one or more inhibitory oligonucleotides (1) hybridize to the second region but are not extended and (2) reduce the amplification of the second region;
thereby generating minority nucleic acid amplification products and total nucleic acid amplification products, wherein the total nucleic acid amplification products are reduced relative to total amplification products that would be generated if no inhibitory oligonucleotide was present, whereby the total nucleic acid amplification products do not dominate the minority nucleic acid amplification products;
(b) separating the minority nucleic acid amplification products and total nucleic acid amplification products, thereby generating separated minority nucleic acid amplification products and total nucleic acid amplification products; and
(c) determining the fraction of the minority nucleic acid species in the sample based on the amount of each of the separated minority nucleic acid amplification products and total nucleic acid amplification products.
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Abstract
The technology relates in part to quantification of a minority nucleic acid species from a nucleic acid sample. In some embodiments, methods for determining the amount of fetal nucleic acid (e.g. absolute amount, relative amount) in a maternal sample are provided.
199 Citations
23 Claims
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1. A method for determining the amount of a minority nucleic acid species in a sample comprising:
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(a) contacting under amplification conditions a nucleic acid sample comprising a minority species and a majority species, the combination of the minority species and the majority species comprising total nucleic acid in the sample, with; (i) a first set of amplification primers that specifically amplify a first region in sample nucleic acid comprising a feature that (1) is present in the minority nucleic acid species and is not present in the majority nucleic acid species, or (2) is not present in the minority nucleic acid species and is present in the majority nucleic acid species, (ii) a second set of amplification primers that amplify a second region in the sample nucleic acid allowing for a determination of total nucleic acid in the sample, wherein the first region and the second region are different, and (iii) one or more inhibitory oligonucleotides, each comprising a nucleotide sequence complementary to a nucleotide sequence in the second region, wherein the one or more inhibitory oligonucleotides (1) hybridize to the second region but are not extended and (2) reduce the amplification of the second region;
thereby generating minority nucleic acid amplification products and total nucleic acid amplification products, wherein the total nucleic acid amplification products are reduced relative to total amplification products that would be generated if no inhibitory oligonucleotide was present, whereby the total nucleic acid amplification products do not dominate the minority nucleic acid amplification products;(b) separating the minority nucleic acid amplification products and total nucleic acid amplification products, thereby generating separated minority nucleic acid amplification products and total nucleic acid amplification products; and (c) determining the fraction of the minority nucleic acid species in the sample based on the amount of each of the separated minority nucleic acid amplification products and total nucleic acid amplification products. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 22)
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12. A method for determining the copy number of a minority nucleic acid species in a sample comprising:
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(a) contacting under amplification conditions a nucleic acid sample comprising a minority species and a majority species, the combination of the minority species and the majority species comprising total nucleic acid in the sample, with; (i) a first set of amplification primers that specifically amplify a first region in sample nucleic acid comprising a feature that (1) is present in the minority nucleic acid species and is not present in the majority nucleic acid species, or (2) is not present in the minority nucleic acid species and is present in the majority nucleic acid species, (ii) a second set of amplification primers that amplify a second region in the sample nucleic acid allowing for a determination of the total nucleic acid in the sample, wherein the first region and the second region are different, (iii) one or more first competitor oligonucleotides that compete with the first region for hybridization of primers of the first amplification primer set, and (iv) one or more second competitor oligonucleotides that compete with the second region for hybridization of primers of the second amplification primer set, thereby generating minority nucleic acid amplification products, total nucleic acid amplification products, first competitor amplification products and second competitor amplification products, wherein each of the minority nucleic acid, total nucleic acid, first competitor and second competitor amplification products are of different lengths; (b) separating the minority nucleic acid amplification products, total nucleic acid amplification products, and competitor amplification products, thereby generating separated minority nucleic acid amplification products, total nucleic acid amplification products, and competitor amplification products; and (c) determining the copy number of the minority nucleic acid species in the sample based on the separated amplification products. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 23)
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Specification