Flatworms can either regrow lost heads or reproduce sexually, not both

Planarians, flatworms identified for his or her goofy cross-eyed gazes, might must make an evolutionary trade-off between regeneration and intercourse – throughout completely different species of planarians, the identical gene signalling pathway facilitates both the flexibility to regrow heads or to supply eggs, relying on whether or not it’s turned on or off. This might assist reply the long-standing thriller of why some animals can regenerate misplaced physique elements whereas others can’t.

That is “truly a extremely previous query within the regeneration subject,” says Jochen Rink …