The "chip" as a specific genetic tool

DNA microarrays are powerful tools for the analysis of the organization and regulation of the brain, in both illness and health. Suck messenger RNA ex pression methods are outgrowths of a marriage between the several genome se quencing projects and a wide variety of physical, chemical, optical, and el ectronic systems. The advantages of microarray analyses include the ability to study the regulation of several genes or even the entire genome in a si ngle experiment. However, there are substantive issues associated with the use of these tools that need to be considered before drawing conclusions ab out the genomic regulation of the brain. These issues include the loss of m ost anatomic (i.e., cellular and circuit) specificity, only fair sensitivit y, lack of absolute quantitative data, poor comparability between studies, and high variability in sample values, to mention the most obvious, In this review we point to some of the solutions proposed for these problems and n ovel techniques and approaches for newer methods. Among these are methods f or making arrays more sensitive, including nonarray messenger RNA expressio n systems. The future of this field and its links to deeper protein and cel l biology are both emphasized (C) 2000 Society of Biological Psychiatry.