Loops of DNA Equipped Ancient Life to Become Complex
5 hours ago
- #genetics
- #evolution
- #marine biology
- Cnidarians and ctenophores are among the oldest known groups of complex animals, evolving between 740 million and 520 million years ago.
- The evolution of complex animals was not due to fundamentally different genes but to how genes were structured and used, particularly through gene regulation.
- Chromatin looping, which brings distant parts of DNA into contact, was a significant step in metazoan evolution, enabling complex gene regulation and cell specialization.
- Enhancers, regulatory DNA sequences far from genes, play a crucial role in gene regulation by allowing genes to be reused in many contexts, contributing to cell-type diversity.
- The study suggests that chromatin looping and distal regulatory elements were key innovations that allowed the rise of complex animals from unicellular ancestors.
- The exact mechanisms of chromatin looping in early metazoans are still unclear, but cohesin proteins are likely involved, similar to their role in advanced metazoans.
- The evolution of complex animals involved a combination of factors, including some genetic novelty and genome expansion, not just chromatin looping.
- The study raises questions about why complexity was latent in unicellular ancestors and whether future regulatory innovations could lead to new forms of life.