Method of sequencing by hybridization of oligonucleotide probes

Abstract

The conditions under which oligonucleotide probes hybridize preferentially with entirely complementary and homologous nucleic acid targets are described. Using these hybridization conditions, overlapping oligonucleotide probes associate with a target nucleic acid. Following washes, positive hybridization signals are used to assemble the sequence of a given nucleic acid fragment. Representative target nucleic acids are applied as dots. Up to to 100,000 probes of the type (A,T,C,G) (A,T,C,G)N8(A,T,C,G) are used to determine sequence information by simultaneous hybridization with nucleic acid molecules bound to a filter. Additional hybridization conditions are provided that allow stringent hybridization of 6-10 nucleotide long oligomers which extends the utility of the invention. A computer process determines the information sequence of the target nucleic acid which can include targets with the complexity of mammalian genomes. Sequence generation can be obtained for a large complex mammalian genome in a single process.

Description

1. INTRODUCTION[0001] The present invention belongs to the field of molecular biology. It involves a novel method of sequencing of a target nucleic acid sequence by hybridization of short oligonucleotide probes to a nucleic acid target. The oligonucleotide probes can comprise all known combinations of the four nucleotides of a given length, i.e. oligonucleotides of base composition adenine (A), thymine (T), guanine (G), and cytosine (C) for DNA and A, G, C, and uridine (U) for RNA. Conditions are described which allow hybridization discrimination between oligonucleotides which are as short as six nucleotides long and have a single base end-mismatch with the target sequence.[0002] The invention is demonstrated by way of examples in which sequence information is generated using the method of the invention.2. BACKGROUND OF THE INVENTION2.1. Hybridization[0003] Hybridization depends on the pairing of complementary bases in nucleic acids and is a specific tool useful for the general reco...

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Benefits of technology

[0025] (1) rapidity, resulting in time effectiveness: (2) elimination of polyacrylamide gel electrophoresis and the intensive manual labor it requires; (3) reliability of the predicted base within the determined sequence due to the hybridization of multiple oligonucleotides to the same base within a target sequence; (4) the possibility of substantial miniaturization of the process; (5) ease of automation; (6) resulting cost effectiveness.3.1. Definitions

Problems solved by technology

Diverse research problems using hybridization of synthetic oligonucleotide probes of known sequence include, amongst others, the different techniques of identification of specific clones from cDNA and genomic libraries; detecting single base pair polymorphisms in DNA; generation of mutations by oligonucleotide mutagenesis; and the amplification of nucleic acids in vitro from a single sperm, an extinct organism, or a single virus infecting a single cell.

An intensive amount of manual labor is required in the preparation of appropriate polyacrylamide gels to resolve small differences in fragment size.

Although the use of electronic robots and computers allows acceleration of the number of base pairs actually determined, preparation of polyacrylamide gels, application of sample, electrophoresis and the subsequent manipulations necessary to obtain high quality autoradiograms that can be read by machines still involve significant intensive, skilled, manual labor for which no substitutes have been found.

The genome of higher eucaryotes has up to a million times greater physical complexity than is the complexity of individual genes it encodes, giving it a a corresponding huge informational complexity.

However, in practice, actual sequencing of at least three times that number of base pairs is required to obtain a reliable sequence for the human genome, thus requiring even more money and time.

Such endeavors present a challenge to the technology of the twentieth century.

Further challenges arise if sequencing projects are extended to include the determination of the genomic sequences of characteristic individuals or species of organisms, especially those that have economic, social or medical importance.

Such identification however does not provide desired and useful sequence information of the DNA in a particular identified fragment.

The number of genetic regions to be scored in the DNA of an individual requires a large number of polymorphic probes and makes the use of traditional Southern blotting unpractical.

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