Microarray Advances

Courtesy of Agilent

Perhaps no technology better embodies the spirit of the post-genomics age than the microarray. If genome sequencing projects listed the parts that make up an organism – be it a mouse, a fly, or a human – DNA microarrays, or "biochips," provide the first real application for that information.

Microarrays are addressable assemblies of nucleotide sequences tethered to a solid surface, each of which represents a single gene, splice variant, or other DNA element. Armed with these tools, scientists can probe the expression of every gene represented on the array – sometimes numbering in the tens of thousands – in parallel, all on the surface of a single glass microscope slide.

They can ask which genes are over- or under-expressed in diseased cells, or in response to drug treatments. They can grade cancers with unprecedented precision, meaning that patients could one day see individually tailored drug regimens,...