Visible Genetics Inc.

Bayer Healthcare LLC

Jean-Michel Lacroix

James M Dunn

James Leushner

May Hui

Marina T Larson

Robert Shipman

Quantitative and qualitative analysis of a nucleic acid analyte in a sample suspected to contain the nucleic acid analyte if achieved by first preparing a reaction mixture containing the sample and a known amount of an internal quantitation standard. At least a first aliquot of the reaction mixture is combined with a set of amplification reagents effective to amplify nucleic acids in the reaction mixture. The set of reagents includes at least one primer pair which is effective to amplify a first region of the nucleic acid analyte if present in the sample to produce a first amplified sample fragment and to amplify at least a portion of the internal quantitation standard to produce a control fragment. Amplification results in the formation of an amplification product mixture containing first amplified sample fragments and control fragments when the nucleic acid analyte is present in the sample, and only control fragments when the nucleic acid analyte is not present in the sample. The relative amounts of first amplified sample fragments and control fragments are analyzed to quantify the amount of nucleic acid analyte in the sample, and the sequence of the first amplified sample fragments is determined to assess the qualitative characteristics of any nucleic acid analyte. The internal quantification fragment is derived from the analyte nucleic acid by the incorporation of a plurality of sequence variations. These sequence variations include at least a first sequence variation effective to render the internal quantitation standard distinguishable from the first amplified sample fragment, and a second sequence variation effective to substantially eliminate the production of sequencing products from interaction of the internal quantitation standard and the first sequencing primer.

Method and kit for quantitation and nucleic acid sequencing of nucleic acid analytes in a sample

A method for obtaining information about the allelic type of a sample of genetic material derived from an HIV-infected sample relies on the observation that using a second nested set of sequencing primers ensures the maximum potential for sequencing a particular sample. To perform the method, reagents suitable for performing the tests are suitably packaged as a kit.

Method and kit for evaluation of HIV mutations

Sequencing of a selected region of a target nucleic acid polymer in a natural abundance DNA sample can be performed in a single vessel by combining the sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as Thermo Sequenase&trade; which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide feedstocks, and a chain terminating nucleotide. The reaction mixture also includes an unconventional nucleotide and an appropriate enzyme for degradation of nucleic acid polymers containing the unconventional nucleotide. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.

Method for sequencing of nucleic acid polymers

Evaluation of a sample for the presence and qualitative nature of a microorganism can be performed in a single vessel by combining a natural abundance DNA sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as ThermoSequenase&trade; which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide triphosphate feedstocks, and a chain terminating nucleotide triphosphate. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.

Method compositions and kit for detection

A method is provided for simultaneously determining the positions of a selected nucleotide base in a target region of both strands of a denatured duplex nucleic acid polymer. The nucleic acid polymer is combined with a reactant mixture comprising first and second oligonucleotide primers, said primers binding to the sense and antisense strands, respectively, of the nucleic acid polymer at a location flanking the target region; a thermostable DNA polymerase; a chain-terminating nucleotide triphosphate complementary to the selected nucleotide base; and other reagents for synthesis of chain extension products to form a reaction mixture. This mixture is processed through a plurality of thermal cycles, each including at least a chain extension phase and a denaturation phase to produce chain extension products. These chain extension products are evaluated to determine the positions of the selected bases. The method of the invention differs from the prior art, because the first and second oligonucleotide primers are each labeled with different, spectroscopically-distinguishable fluorescent labels. The method therefore obtains information about both DNA strands simultaneously while providing improved sensitivity as a result of the non-linear increase in the amount of DNA which results from the production of additional templates molecules from unterminated fragments.

Method for bi-directional sequencing of nucleic acid polymers

A streamlined, hierarchical method for obtaining information about the allelic type of a sample of genetic material derived from an HIV-infected sample relies on the observation that 93-95% of the known mutational variants of the reverse transcriptase and protease genes of HIV-1 can be determined by evaluating the positions of the A and T nucleotides within the sample. Thus, a substantial fraction of all mutational variations can be unequivocally identified by performing two initial sequencing reactions on the sample in which only ddA and ddT are used as chain terminators. For the small fraction of samples which are not identifiable based on the positions of these two bases, a second test is performed in which the sequence is determined in the 3'-direction for all four bases. This test will identify substantially all of the remaining samples. For those for which an ambiguity remains, however, a final test in which the sequence of the sample is determined in both the 3' and 5-direction for all four bases is performed. To perform the method, reagents suitable for performing the three tests within the hierarchy are suitably packaged as a kit containing two or more sub-kits. The first sub-kit contains reagents for performing A and T sequencing. The additional sub-kits contains reagents for performing a four-base sequence determination on one or both strands of the target DNA.

Evaluation of a sample for the presence and qualitative nature of a microorganism can be performed in a single vessel by combining a natural abundance DNA sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as ThermoSequenase.TM. which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide triphosphate feedstocks, and a chain terminating nucleotide triphosphate. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.

Method, compositions and kit for detection and identification of

A method for quantitative and qualitative analysis of a nucleic acid analyte in a sample suspected to contain the nucleic acid analyte first combines the sample with a control nucleic acid, and two primer pairs, a first primer pair effective to amplify a conserved region of the nucleic acid analyte if present in the sample to produce a conserved fragment having a first length and to amplify the control nucleic acid to produce a control fragment having a second length different from the first length, and a second primer pair effective to amplify a second region of the nucleic acid analyte to produce a sequencing fragment. One member of the first primer pair is labeled with a detectable label, and one member of the second primer pair may be labeled with a label such as biotin effective to permit capture of the primer. The combined mixture is then processed to amplify the sample and control nucleic acid using the first and second primer pairs to produce an amplification product mixture containing conserved fragments, sequencing fragments and control fragments when the nucleic acid analyte is present in the sample, and only control fragment when the nucleic acid analyte is not present in the sample. This product mixture is analyzed to determine the relative amounts of conserved fragments and control fragments in the amplification product mixture to quantify the amount of nucleic acid analyte in the sample and used as a starting point for a reaction to determine the sequence of the sequencing fragment.

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Etobicoke, Canada

Jean-Michel Lacroix