Abstract: Disclosed is a kit useful for determining the number of repeat units in a repeat region of a target nucleic acid comprising: a plurality of different-sequence primers, each containing (i) a target binding segment and (ii) a tag segment having a nucleotide sequence that uniquely identifies the target binding segment, a first primer extension reagent; and a second primer extension reagent, wherein at least one of the first or second primer extension reagents includes an extendible nucleotide having a photodestructible label attached thereto.

Abstract: Disclosed is a method for determining the number of repeat units in a repeat region of a target nucleic acid. In a first aspect, the method of the invention includes the steps of annealing a primer to a target nucleic acid; performing a first primer extension reaction using a first primer extension reagent; separating the target-primer hybrid and unreacted first primer extension reagent; performing a second primer extension reaction using a second primer extension reagent, wherein at least one of the first or second primer extension reagents includes an extendible nucleotide having a label attached thereto; separating the target-primer hybrid from unreacted second primer extension reagent; measuring a signal produced by the label; treating the label so as to render the label undetectable; and repeating the above steps until the signal is substantially less than a signal detected in a previous cycle.

Abstract: Disclosed is a method for determining the number of repeat units in a repeat region of a target nucleic acid. In a first aspect, the method of the invention includes the steps of annealing a primer to a target nucleic acid; performing a first primer extension reaction using a first primer extension reagent; separating the target-primer hybrid and unreacted first primer extension reagent; performing a second primer extension reaction using a second primer extension reagent, wherein at least one of the first or second primer extension reagents includes an extendible nucleotide having a label attached thereto; separating the target-primer hybrid from unreacted second primer extension reagent; measuring a signal produced by the label; treating the label so as to render the label undetectable; and repeating the above steps until the signal is substantially less than a signal detected in a previous cycle.

Abstract: Disclosed is a method for determining the number of repeat units in a repeat region of a target nucleic acid. In a first aspect, the method of the invention includes the steps of annealing a primer to a target nucleic acid; performing a first primer extension reaction using a first primer extension reagent; separating the target-primer hybrid and unreacted first primer extension reagent; performing a second primer extension reaction using a second primer extension reagent, wherein at least one of the first or second primer extension reagents includes an extendible nucleotide having a label attached thereto; separating the target-primer hybrid from unreacted second primer extension reagent; measuring a signal produced by the label; treating the label so as to render the label undetectable; and repeating the above steps until the signal is substantially less than a signal detected in a previous cycle.

Abstract: A method for obtaining sequence information from a plurality of target polynucleotides in a sample is disclosed. In one embodiment, the method involves contacting a plurality of different sequence primers with a polynucleotide sample under conditions effective for the primers to anneal to primer-complementary regions in one or more target polynucleotides, to form one or more target-primer hybrid(s). Each different-sequence primer contains (i) a target binding segment and (ii) a tag segment having a nucleotide sequence that uniquely identifies the target binding segment. The hybrid(s) are contacted with a labeled nucleotide terminator in the presence of a primer-extending reagent, under conditions effective to append the base to an end of the annealed primer in the hybrid only when the base is complementary to a base in the target polynucleotide that is immediately adjacent to the end of the annealed primer, to form an extended hybrid mixture.

Abstract: Disclosed is a method for determining the number of repeat units in a repeat region of a target nucleic acid. In a first aspect, the method of the invention includes the steps of annealing a primer to a target nucleic acid; performing a first primer extension reaction using a first primer extension reagent; separating the target-primer hybrid and unreacted first primer extension reagent; performing a second primer extension reaction using a second primer extension reagent, wherein at least one of the first or second primer extension reagents includes an extendible nucleotide having a label attached thereto; separating the target-primer hybrid from unreacted second primer extension reagent; measuring a signal produced by the label; treating the label so as to render the label undetectable; and repeating the above steps until the signal is substantially less than a signal detected in a previous cycle.

Abstract: The invention relates to improved methods and compositions for loading samples into an analytical instrument having a plurality of sample receiving loading ports. In a principle embodiment of the invention, first and second sample markers are added to sample to be loaded onto an analytical instrument having a plurality of sample receiving loading ports. The first and second samples are compounds are selected so as to produce a distinctive signal upon combination thus a sample containing a first sample marker and a sample containing a second marker are mistakenly loaded into the same sample receiving loading port, a detectable signal indicative of the misloading is produced.

Abstract: In a first aspect, the method of the invention includes the steps of annealing a primer to a target nucleic acid; performing a first primer extension reaction using a first primer extension reagent; separating the target-primer hybrid and unreacted first primer extension reagent; performing a second primer extension reaction using a second primer extension reagent, wherein at least one of the first or second primer extension reagents includes an extendible nucleotide having a label attached thereto; separating the target-primer hybrid from unreacted second primer extension reagent; measuring a signal produced by the label; treating the label so as to render the label undetectable; and repeating the above steps until the signal is substantially less than a signal detected in a previous cycle.