A bid to map gene expression to specific cells in the mouse brain involved some 60 full-time scientists — from technicians to the project's scientific board. The $41-million project, run by the Allen Institute for Brain Science in Seattle, Washington, culminated this week with a three-dimensional atlas of the mouse brain, which shows that 80% of all mouse genes are activated in the building of the brain (see page 168).

Technicians took brain slices and then probed them for specific genes using a high-throughput in situ hybridization process. They photographed them with automated microscopes and then uploaded the results to a server.

The group's members came from a wide range of backgrounds. Paul Allen, co-founder of Microsoft as well as sponsor of the Allen Institute, contributed a team of software developers from his venture-capital firm Vulcan. Other members included former Boeing engineers, classically trained neuroanatomists, image-processing specialists, robotics experts and a cadre of young technicians.

The trick to making all the pieces fit together was creating operating procedures, standardized data quality, data-delivery benchmarks and a highly automated system for labelling data, says Allan Jones, the Allen Institute's chief scientific officer.