A microarray is essentially, an ordered array of DNA or any nucleic acids. It’s typically gridded out onto some kind of solid support, so that, basically in a very small area, let’s say a microscope slide, you can put down every single gene in the genome, forty, fifty-thousand genes in that small area. And you can basically then, in a very quick hybridization experiment, if you label, let’s say, different patients or different people's DNA, you can hybridize them on and basically measure, with fluorescent signal, how much of each DNA is binding to each part of the genome. So in basically one step, in a few hours or in twenty-four hours, you can assess the entire genome of an individual or a species for changes in copy number, for changes in expression, etc. So, essentially what it has done is given us the ability, rather than looking one gene at a time at specific things or a few genes at a time, to be able to look at the whole system of the genome in parallel. So it really has brought us into this area of genome systems biology. So we can look at the entire genome of an individual or a person or a treatment or anything, kind of at once, very, very efficiently and very cheaply now.