Patent ID: 6372434
Filing Date: 2002-04-16
Classification: C12N,C12Q,Y10S,Y10T

Abstract:
A method for selectively recovering heterohybrid DNA from a reannealed mixture of two DNA samples, wherein the heterohybrid DNA has one strand derived from a first sample, and one strand derived from a second sample, comprising:(a) methylating both strands of the first sample but not the second sample with enzyme DAM methylase; (b) methylating both samples with a methylase that protects all restriction sites recognized and cleaved by a restriction enzyme against cleavage by said restriction enzyme such that either strand of a duplex will be protected from cleavage by said restriction enzyme; (c) ligating to both first and second samples Y-shaped adapters that have a first and second site for said restriction enzyme such that the upper strand of the first site and the lower strand of the second site are methylated in adapters ligated to the first sample and the lower strand of the first site and the upper strand of the second site are methylated in the second sample; (d) denaturing, mixing, and reannealing the samples obtained in (c); (e) cleaving the samples with restriction enzymes Dpn1 and Mbo1 to destroy all homohybrids; and (f) selectively recovering heterohybrid DNA so produced.