Genes & the Inheritance of Memories Across Generations | Dr. Oded Rechavi

DNA contains the complete genetic instructions (genome), RNA acts as specific instructions for building things, and proteins are the functional 'furniture' built from these instructions.

The concept is controversial due to historical frauds (like Paul Kammerer) and devastating political misuse (like Lysenkoism in the Soviet Union), which cast a long shadow over the field, making it a scientific taboo for decades.

Environmental factors like famine or stress experienced by parents can affect offspring's birth weight, glucose sensitivity, and neurological disease risk. However, it's often hard to definitively separate direct environmental exposure from true transgenerational epigenetic inheritance in mammals.

Model organisms like C. elegans are vital because they share a common ancestor and many fundamental biological functions with humans. Their ease of manipulation, short generation times, and well-understood genetics allow for controlled experiments impossible in humans, providing insights into complex biological processes and diseases.

C. elegans can inherit resistance to viruses across multiple generations through small RNA molecules. If parent worms are infected, their offspring, even those genetically unable to produce their own small RNAs, will inherit these protective RNAs and resist the virus.

Worms possess a unique machinery called RNA dependent RNA polymerase, which amplifies the small RNA molecules in each subsequent generation. This amplification prevents the dilution of the inherited RNA, allowing the trait to persist for several generations.

While arbitrary memories (like a phone number) are unlikely to be inherited due to the different 'languages' of brain circuits and molecular inheritance, more general or specific responses (like a change in a receptor's expression) could potentially be transmitted if translated into a molecular form, though the mechanism for this brain-to-germline translation in mammals is still unclear.

If hermaphrodite worms are exposed to high temperatures, their offspring for three generations will mate significantly more with males. This occurs because the temperature stress compromises sperm production in the hermaphrodites, causing them to secrete a pheromone that attracts males to ensure continued reproduction.

Future applications could include diagnostics, where RNA profiles might correlate with disease risks, offering a new level of screening beyond DNA. It might also open avenues for interventions, such as modifying parental behaviors (e.g., exercise) to positively influence offspring's RNA profiles for healthier outcomes.

Placing C. elegans on ice after learning an association prevents them from forgetting, extending their memory significantly. This effect is not merely due to slowed metabolism but involves an internal state change related to cold tolerance, which can be manipulated by specific genes and even lithium, a drug used for bipolar disorder.