Sequencing using end-labelled DNA

In these procedures the DNA fragment to be sequenced is initially labelled, at either the 3 - or 5 -ends with [32P] and the DNA chain is cleaved by a set of base-specific reactions to yield families of end-labelled fragments which are separated from each other by electrophoresis on sequencing gels, in exactly the same way as the primed-synthesis fragments are identified. 

The most widely used procedure for cleaving the end-labelled DNA fragments are the base-specific chemical degradation reac- 

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