Do jellyfish and sea anemones sleep like humans?

Jellyfish and sea anemones exhibit sleep-like states where they reduce their activity, allowing their nerve cells to repair DNA damage that accumulates during wakefulness.

What is the main purpose of sleep in ancient organisms?

The research suggests that the fundamental purpose of sleep in ancient organisms, including jellyfish and anemones, is to repair DNA damage in their nerve cells.

When did sleep likely evolve according to new research?

New findings suggest that sleep, for the purpose of DNA repair, likely evolved over 600 million years ago, before the split of major animal lineages and the development of brains.

Home / Science / Jellyfish Sleep: DNA Repair Key to Ancient Life

Jellyfish Sleep: DNA Repair Key to Ancient Life

27 Jan

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Summary

Jellyfish and anemones exhibit sleep-like behavior, repairing DNA.
Sleep in simple invertebrates suggests its ancient origin predates brains.
DNA repair during rest is a fundamental function of sleep.

Jellyfish Sleep: DNA Repair Key to Ancient Life

A recent study published in Nature Communications has uncovered that simple invertebrates, such as jellyfish and sea anemones, enter sleep-like states to perform essential cellular repair. These creatures, belonging to a lineage over 500 million years old, show a significant reduction in neural activity during rest periods, during which damage to their DNA accumulates during wakefulness is repaired. This discovery pushes back the evolutionary origins of sleep to before the divergence of major animal groups, suggesting that sleep's fundamental purpose is cellular maintenance.

Researchers observed that nerve cells in jellyfish and anemones experienced increased DNA breaks after periods of activity. During their respective rest phases, these breaks were mended, mirroring processes previously observed only in vertebrates. The study also indicated that melatonin, a hormone associated with sleep in animals with brains, influences these brainless creatures to rest, suggesting an even earlier evolution of sleep's regulatory mechanisms. This research strengthens the hypothesis that sleep began as a vital cellular defense strategy.