The genomic sequencing technique.

Our method extends the Southern blotting technique to a new degree of sensitivity . \.J'e use a radioactive probe not just to identify a single r estriction fragment of DNA but as a way of end-labeling a unique restriction fragment. This endlabel ing by hybridization is analogous to the endlabeling that we do in the conventional DNA sequencing , which enables us to display in any partial di gest a series of fragments extending out f r om the point of label ing as a series of labeled bands separated by size . Although the chemical DNA sequencing techniques usually use onl y a single labeled phosphate, if the hybridization probe is kept moderately short, on the order of 100 nucleotides , it will serve as a endlabel that can display sequence running out several hundr ed bases beyond the end of the probe .