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Update on target theory as applied to chromosomal aberrations
Author(s) -
Savage John R. K.
Publication year - 1993
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850220404
Subject(s) - chromosome , metaphase , interphase , biology , physics , genetics , evolutionary biology , gene
The early radiobiologists, who developed target theory to explain their results, considered the chromosome “target” as a visible thread that could be physically broken by ionizing radiation. Most of the broken ends restituted, but those that did not were free to wander about and, within limits, could rejoin with any other broken end they happened to contact to form structural aberrations. Failing this, they could remain to be seen as “open” breaks at the subsequent metaphase. These ideas, and their inevitable consequences, still form the basis for much modern thinking, even though we now know that the structure of the chromosome, and of the interphase nucleus, are very much more complicated than the originators of the theory envisaged. Current understanding of chromosomes of the molecular level and the varied responses a cell can mobilize when damage is introduced, raise again the question, Can we still think in terms of simple targets? Some of the experimental observations and suggestions made since those early days are reviewed, and the application of target theory to the three theories of aberration origins (Classic, Exchange, Recombination) is briefly discussed. © 1993 Wiley‐Liss, Inc.