Abstract: The invention provides methods of preparing nucleic acids, such as RNA molecules, of a defined size or range of sizes. The invention provides compositions, methods and kits for use in the production and preparation of small RNA molecules (including without limitation micro-RNA, siRNA, d-siRNA and e-siRNA) and other nucleic acids of various sizes.

Abstract: The invention provides methods of preparing nucleic acids, such as RNA molecules, of a defined size or range of sizes. The invention provides compositions, methods and kits for use in the production and preparation of small RNA molecules (including without limitation micro-RNA, siRNA, d-siRNA and e-siRNA) and other nucleic acids of various sizes.

Abstract: An improved separation column and method for separating a mixture of double stranded DNA fragments by Matched Ion Polynucleotide Chromatography. The cylindrical column has an ID greater than about 5 mm and contains polymer beads. The beads have an average diameter of 1 to 100 microns and are unsubstituted polymer beads or are polymer beads substituted with a hydrocarbon moiety having from 1 to 1,000,000 carbons. The preferred beads are characterized by being substantially free from multivalent cations which are free to bind with DNA. The improved column provides enhanced separation of DNA fragments with sizes ranging from about 100 to 20,000 base pairs. The column also provides enhanced separation of heteroduplex and homoduplex DNA molecules in a mutation detection procedure in which the chromatography is performed under conditions effecting partial denaturation of DNA at a site of mismatched base pairs.

Abstract: In one aspect, the present invention concerns an improved method for the preparation of cDNA libraries. Preferred embodiments of the invention include methods and systems capable of generating cDNA libraries enriched for high molecular weight cDNA inserts. The method generally entails the following steps: (1) size-based separation of a plurality of mRNA molecules by Ion-Pairing Reversed-Phase Chromatography (IP-RPC), preferably using HPLC under denaturing conditions; and (2) collection of a fraction of the mRNA molecules that is enriched for mRNA molecules of a desired size range (in a preferred embodiment of the invention, larger-sized mRNA molecules are collected, e.g., mRNA of length greater than 10 kb). The collected fraction of mRNA molecules can be reverse transcribed to form a library of cDNA inserts enriched for inserts of a desired relative size range.

Abstract: An improved separation column and method for separating a mixture of double stranded DNA fragments by Matched Ion Polynucleotide Chromatography. The cylindrical column has an ID greater than about 5 mm and contains polymer beads. The beads have an average diameter of 1 to 100 microns and are unsubstituted polymer beads or are polymer beads substituted with a hydrocarbon moiety having from 1 to 1,000,000 carbons. The preferred beads are characterized by being substantially free from multivalent cations which are free to bind with DNA. The improved column provides enhanced separation of DNA fragments with sizes ranging from about 100 to 20,000 base pairs. The column also provides enhanced separation of heteroduplex and homoduplex DNA molecules in a mutation detection procedure in which the chromatography is performed under conditions effecting partial denaturation of DNA at a site of mismatched base pairs.

Abstract: In one aspect, the present invention concerns an improved method for the preparation of cDNA libraries. Preferred embodiments of the invention include methods and systems capable of generating cDNA libraries enriched for high molecular weight cDNA inserts. The method generally entails the following steps: (1) size-based separation of a plurality of mRNA molecules by Ion-Pairing Reversed-Phase Chromatography (IP-RPC), preferably using HPLC under denaturing conditions; and (2) collection of a fraction of the mRNA molecules that is enriched for mRNA molecules of a desired size range (in a preferred embodiment of the invention, larger-sized mRNA molecules are collected, e.g., mRNA of length greater than 10 kb). The collected fraction of mRNA molecules can be reverse transcribed to form a library of cDNA inserts enriched for inserts of a desired relative size range.

Abstract: An improved separation column and method for separating a mixture of double stranded DNA fragments by Matched Ion Polynucleotide Chromatography. The cylindrical column has an ID greater than about 5 mm and contains polymer beads. The beads have an average diameter of 1 to 100 microns and are unsubstituted polymer beads or are polymer beads substituted with a hydrocarbon moiety having from 1 to 1,000,000 carbons. The preferred beads are characterized by being substantially free from multivalent cations which are free to bind with DNA. The improved column provides enhanced separation of DNA fragments with sizes ranging from about 100 to 20,000 base pairs. The column also provides enhanced separation of heteroduplex and homoduplex DNA molecules in a mutation detection procedure in which the chromatography is performed under conditions effecting partial denaturation of DNA at a site of mismatched base pairs.

Abstract: The instant invention provides a method for stabilizing an RNA molecule against degradation comprising applying a solution to a separation medium having a non-polar separation surface in the presence of a counterion agent, wherein the solution comprises the RNA molecule and an agent capable of catalyzing the degradation of RNA; eluting the RNA molecule from the separation medium by passing through the separation medium a mobile phase containing a concentration of organic solvent sufficient to elute the RNA molecule from the separation medium, where the elution is conducted under conditions that result in a substantial separation of the RNA molecule from the agent capable of catalyzing the degradation of RNA; and collecting an eluant fraction containing the RNA molecule that is substantially free of the agent capable of catalyzing the degradation of RNA. In a preferred embodiment the method is performed under conditions that are substantially free of multivalent cations.