Book Viewer

Short Contents | Full Contents | Other books @ NCBI

| Modern Genetic Analysis Chapter 7. Gene Mutations The Molecular Basis of Mutation Figure 7-26. Schemes for postreplication repair. (a) In recombinational repair, replication jumps across a blocking lesion, leaving a gap in the new strand. A recA-directed protein then fills in the gap, using a piece from the opposite parental strand (because of DNA complementarity, this filler will supply the correct bases for the gap). Finally, the RecA protein repairs the gap in the parental strand. (b) In SOS bypass, when replication reaches a blocking lesion, the SOS system inserts the necessary number of bases (often incorrect ones) directly across from the lesion and replication continues without a gap. Note that, with either pathway, the original blocking lesion is still there and must be repaired by some other repair pathway. (Adapted from A. Kornberg and T. Baker, DNA Replication, 2d ed. Copyright © 1992 by W. H. Freeman and Company, New York.)

© 1999 by W. H. Freeman and Company. All rights reserved.