AN ONLINE database should help reveal the underlying causes of some diseases by showing which genes are switched on or off in healthy human tissue.
To work out which genes are involved in a particular disorder, researchers have to compare gene expression in diseased tissue with that in normal tissue. But existing databases of normal gene expression are unreliable because they are based on very few samples, says Javed Khan of the National Institutes of Health in Bethesda, Maryland.
So his team took 158 samples from 30 people of various ages and ethnicities and mapped the expression of nearly 19,000…
