Isomap analysis of the high throughput screening data set human 6800 arrays. Isomap models were generated from 30 human 6800 high density oligonucleotide arrays with 7,129 genes on each array as described in Systems and Methods. Panel A shows a three-dimensional Isomap model. Panel B shows a two-dimensional Isomap model. Arrows point to the directions of the monocytic and granulocytic differentiation. Panel C shows the residual variance after the application of Isomap, MDS, and PCA models. Neighborhood size: k = 5. See text for more detail. Animated image is presented in Additional file 4.