ABSTRACT
As concern grows that human populations are being exposed to an ever-increasing number of potentially harmful agents, the field of developmental toxicology has become a national research priority (1). Understanding how embryos respond inappropriately to drugs and chemicals remains a central question in the field. Toward the end of the 20th century, it was well demonstrated that chemical agents could perturb transitory genetic signals and responses that direct morphogenesis through direct mechanisms (2,3) or through cellular damage (4,5). Moving into the 21 st century, we are gaining wider appreciation of the consequences of teratogenic insult on molecular homeostasis of the embryo (6). DNA microarray analysis, which has become a widely used tool for the generation of gene-expression data on a genomic scale, is a newer technology that is increasingly being applied to experimental teratology for large-scale analysis of gene expression (7,8).
