On a balmy day the thermostat in Nancy Hopkins' lab in the Center for Cancer Research on the MIT campus is set to a temperature that is uncomfortably warm-for humans, anyway. It's fine for the other occupants: minnow-sized striped zebra fish that populate the plastic tanks stacked against one wall. Around here, what the fish need, the fish get. Hopkins is fervent about the fish because she believes that they will repay her with something of immeasurable value: a fundamental understanding of life and disease.

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