Scientific Discovery
- A landmark 2024 study published inCell showed that rice plants (Oryza sativa) can adapt to cold via epigenetic changes, not DNA mutations.
- This cold tolerance was induced by environmental exposure and passed down for five generations.
- Suggests that inheritance can happen without changes in DNA sequence, giving credence to Lamarck’s theory of acquired traits.
Relevance : GS 1(Environment and Ecology)
Mechanism: Epigenetics & ACT1 Gene
- The gene ACT1 (involved in growth and development) is normally highly expressed.
- Cold exposure leads to epigenetic silencing of ACT1 in normal rice via methylation (adding a methyl group to DNA).
- Cold-adapted rice did not methylate ACT1, maintaining its expression and enabling survival in low temperatures.
- These epigenetic marks were heritable, improving seed quality from 2nd generation onwards, and persisted across 5 generations.
Experimental Details
- Researchers assessed adaptation by tracking seed quantity and quality over generations.
- Whole genome sequencing of cold-adapted vs. normal rice revealed:
- No clear DNA mutations explaining the trait.
- 12,380+ epigenetic differences, especially near ACT1.
- Confirms that gene expression, not gene sequence, underlies the observed adaptation.
Historical Context & Theoretical Implications
- Lamarck’s theory (1809): Traits acquired during life can be inherited.
- Darwin’s theory (1859): Traits evolve via natural selection of random mutations.
- Epigenetics bridges both: traits can be inherited without DNA changes, via chemical tags regulating gene activity.
- Previous evidence was weak or inconclusive—this rice study provides robust proof in a natural organism.
Significance for Evolutionary Biology
- Reopens debate on Lamarckian inheritance in the molecular era.
- Suggests that environmental stress can directly influence heredity in ways beyond Darwinian mutation and selection.
- Offers new insights into crop resilience, climate adaptation, and non-genetic inheritance.
