Abstract: A method in which a temperature gradient is generated across a “gradient” block, and an apparatus comprising a block across which a temperature gradient can be generated. By setting up such a gradient, multiple reaction mixtures held in wells on the gradient block can be simultaneously run at temperatures which differ only slightly, thereby permitting an optimum temperature for the reaction to be quickly identified. In a preferred embodiment the gradient block is integrated into a thermal cycler used for nucleic acid amplification reactions.

Abstract: A method in which a temperature gradient is generated across a “gradient” block, and an apparatus comprising a block across which a temperature gradient can be generated. By setting up such a gradient, multiple reaction mixtures held in wells on the gradient block can be simultaneously run at temperatures which differ only slightly, thereby permitting an optimum temperature for the reaction to be quickly identified. In a preferred embodiment the gradient block is integrated into a thermal cycler used for nucleic acid amplification reactions.

Abstract: A method in which a temperature gradient is generated across a “gradient” block, and an apparatus comprising a block across which a temperature gradient can be generated. By setting up such a gradient, multiple reaction mixtures held in wells on the gradient block can be simultaneously run at temperatures which differ only slightly, thereby permitting an optimum temperature for the reaction to be quickly identified. In a preferred embodiment the gradient block is integrated into a thermal cycler used for nucleic acid amplification reactions.

Abstract: A method in which a temperature gradient is generated across a "gradient" block, and an apparatus comprising a block across which a temperature gradient can be generated. By setting up such a gradient, multiple reaction mixtures held in wells on the gradient block can be simultaneously run at temperatures which differ only slightly, thereby permitting an optimum temperature for the reaction to be quickly identified. In a preferred embodiment the gradient block is integrated into a thermal cycler used for nucleic acid amplification reactions.

Abstract: An oligonucleotide library is described that is1 useful for producing an oligonucleotide of preselected sequence comprising a plurality of oligonucleotide members comprising one or more oligonucleotide species and having the compositional formula (X).sub.a (N).sub.b ; wherein X represents a non-degenerate nucleotide base and N represents a degenerate nucleotide base; "a" represents the number of non-degenerate nucleotide positions and is from 3 to 8; "b" represents the number of degenerate nucleotide positions and is from 0 to 4 but not greater that "a"; and wherein each of the oligonucleotide species is capable of forming a hybridization complex with at least one other of the oligonucleotide species in the library such that a single ligation event of the hybridization complex with another hybridization complex derived from the library produces a ligation reaction product comprising greater than 12 contiguous nucleotide base pairs.

Abstract: A method in which a temperature gradient is generated across a "gradient" block, and an apparatus comprising a block across which a temperature gradient can be generated. By setting up such a gradient, multiple reaction mixtures held in wells on the gradient block can be simultaneously run at temperatures which differ only slightly, thereby permitting an optimum temperature for the reaction to be quickly identified. In a preferred embodiment the gradient block is integrated into a thermal cycler used for nucleic acid amplification reactions.