Scientists have discovered 15 genome sites — the first ever — linked to depression in people of European ancestry. Many of these regions of depression-linked genetic variation turn out to be involved in regulating gene expression and the birth of new neurons in the developing brain.

But – in a twist – the researchers didn’t have to sequence anyone’s genes! Instead, they analyzed data already shared by people who had purchased their own genetic profiles via an online service and elected to participate in its research option. This made it possible to leverage the statistical power of a huge sample size to detect weak genetic signals associated with a diagnosis likely traceable to multiple underlying illness processes.