Why do we sleep? This is a question that has bedeviled researchers for decades. But we think one major reason may be to facilitate DNA repair. In this episode of humanOS Radio, Dan speaks with Lior Appelbaum. Dr. Appelbaum and colleagues have performed some elegant studies elucidating the molecular mechanisms that underlie sleep, using zebrafish as a model organism. In a recent study, the team engineered zebrafish larvae to express colorful tags on their chromosomes, making it easy to monitor them. They then followed the activity of the chromosomes in their neurons, as well as DNA damage and repair, and were surprised by what they observed. To learn about their findings, check out the interview!