It is the sequence of the nucleotide bases in the DNA molecule that is fundamental to nucleic acid function. Hence the techniques that determine this sequence are extremely important in recombinant DNA technology. Two similar methods have been developed. Both depend on the production of a mixture of oligonucleotides labelled either radioactively or with fluorescein, with one common end and differing in length by a single nucleotide at the other end. This mixture of oligonucleotides is separated by high resolution electrophoresis on Polyacrylamide gels and the position of the bands determined.
Known DNA sequences associated with specific genes are stored in computer libraries which are freely accessible. This allows the comparison of newly sequenced genes with those coding for known proteins.
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