Biology Reference
In-Depth Information
13
Biomarkers of Genotoxicity for In Situ Studies
at Individ ual and Population Levels
Paule Vasseur, Franck Atienzar, Carole Cossu-Leguille,
François Rodius, and Sébastien Lemière
CONTENTS
13.1 Introduction ........................................................................................................................ 327
13.2 In Situ Biomarkers of Exposure to Genotoxic Pollutants ............................................. 328
13.2.1 DNA Adducts ......................................................................................................... 328
13.2.2 Cytogenetic Assays and MN Test ........................................................................ 336
13.2.3 Comet Assay ........................................................................................................... 338
13.2.4 Oxidative DNA Damage ....................................................................................... 341
13.2.5 Mutations ................................................................................................................ 342
13.2.6 Biomolecular Techniques for Genomic and Transcriptomic Studies ............. 343
13.3 Genotoxicity, Physiological, and Populational Effects ................................................. 346
13.3.1 Exxon Valdez Accident ............................................................................................ 346
13.3.2 Genotoxicity, Population Genetics, and Environmental Contamination ...... 347
13.4 Quality Threshold for Health Safety .............................................................................. 349
13.5 Conclusions ......................................................................................................................... 350
Acknowledgment ........................................................................................................................ 351
References ..................................................................................................................................... 351
13.1 Introduction
In every living organism, the genome governs cell functioning in response to signals from
its environment. Any physical or chemical agent capable of interfering with these signals
through genetic and epigenetic mechanisms may be toxic for cell cycle, growth, division,
and differentiation.
For decades, genomic disturbances have been considered to be a result of alteration in
the primary structure of DNA. The genetic material is known to encode all the information
necessary for an organism to grow, divide or reproduce, and die. DNA structural integrity
has been seen as essential in life. Nowadays, epigenetic phenomena have been discovered
to be fundamental for proper development and cellular differentiation within normal tis-
sues. The term epigenetics refers to functionally relevant modifications to the genome that
do not involve a change in the nucleotide sequence. Examples of such changes are DNA
methylation and histone deacetylation, both of which suppress gene expression without
altering the sequence of the silenced genes. Despite these advances and active research in
cancer development, there is still little knowledge on the pathology of epigenetic changes
327
 
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