ABSTRACT
As environmental degradation resulting from human activities continues, the need for sensitive, accurate, and repeatable assays for use in risk assessment increases. Biomarkers are the biochemical, molecular, physiological, morphological, or behavioral responses that result from toxic action of chemicals to which the organism is exposed. This chapter reviews the application of chromosome analyses, micronucleus assays, and flow cytometry to studies of environmental contamination and its effects on vertebrate animals. It explains the potential use of these procedures in blood and other tissues that can be obtained by relatively noninvasive biopsy. One of the most widely used procedures for chromosome studies is the shortterm leukocyte culture. This procedure is commonly used in medical labs and simply requires a sterile blood sample from which leukocytes are extracted and cultured. Micronuclei are observed as small pieces of chromatin outside the nucleus in cells that normally have only a single nucleus or in mature mammalian red blood cells that normally have no nucleus.
