MENTION the words “billionaire” and “Microsoft” in the same
sentence, and the mind turns naturally to the name William Henry
Gates III. But Bill Gates's original accomplice, Paul Allen, is
not short of a dollar, either. Like Mr Gates, Mr Allen has
devoted part of his fortune to charity. But whereas Mr Gates's
billions are combating various diseases that plague poor
countries, Mr Allen's cash has been focused on a single project.
The full title of his organisation is the Allen Institute for
Brain Science, and the project—just completed—is an atlas of the
brain.  The brain is the most complex organ in the body. Indeed,
it could be argued that it is the most complex object in the
known universe, and it is only recently that tools sophisticated
enough to examine it in detail have been developed. The Allen
Institute has used one of these tools, known as in-situ
hybridisation, to look at the activity in the brain of almost
every gene in the genome. The result is available to all at
When a gene is active it produce