Patent ID: 7115370

Claim:
A method, comprising: a) obtaining a DNA attached to an anchor; b) cleaving said DNA with a first restriction endonuclease (“A”) to release restriction fragments therefrom; c) removing said released fragments while retaining said cleaved DNA using the anchor; d) cleaving said retained DNA with a second restriction endonuclease (“B”) different from said first endonuclease, wherein said cleaving results in releasing a fragment mixture comprising: i) A/B fragments having nonidentical A and B restriction sites on opposing ends; and ii) B/B fragments having the same B restriction sites on opposing ends; and e) separating said A/B fragments from said B/B fragments by a method that comprises: i) ligating said fragment mixture with A linkers recognizing and binding said A restriction site and B linkers recognizing and binding said B restriction sites, wherein said A linkers are attached to an anchor, and said B linkers are not attached to such an anchor; ii) retaining said A/B fragments by immobilizing fragments using the anchor on the A linkers; and iii) discarding fragments that have not been immobilized.