DNA arrays: technology, options and toxicological applications

The human genome contains an estimated 3 billion bases of DNA making up som e 100000 genes, and the variation within this genome accounts for human div ersity and, in many cases, disease. Defining and understanding the expressi on profile of given genotypes is essential to understanding adverse effects from acute or chronic exposure to environmental toxicants or other stimuli . DNA array technology could help researchers understand how organisms func tion in response to exposure by elucidating the molecular mechanisms that u nderlie them. DNA arrays have been developed and refined over the past 5 ye ars and matured into a relatively accessible and affordable technology. The y vary in design from membrane-based filters with a few hundred cDNAs, to g lass-based 'chips' with tens of thousands of generic elements. Mammalian DN A arrays will soon allow expression analysis on a genome-wide scale, simila r to that already accomplished in some lower organisms (e.g. S. cerevisiae, E. coli). These whole-genome arrays will be powerful tools for identifying and characterizing toxicants in environmental and pharmaceutical science. This review discusses the technology behind the production of DNA arrays, t he options available to those interested in applying them to their own rese arch, and the possible toxicological applications of this exciting new tech nology.