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

Andrew Huberman opens by setting up an intuitive contrast. Most people accept that two blue-eyed parents are more likely to have a blue-eyed child than a brown-eyed one. Most people also assume that a parent who spends years studying architecture will not pass that knowledge to their children through DNA. Any advantage the children have would come from being exposed to architecture at home, which is nurture rather than inheritance. Huberman asks Dr. Oded Rechavi to explain why eye color is thought to be inherited and knowledge is not. He also asks about the evidence that, contrary to that intuition, some kinds of knowledge at the level of cells and systems can be inherited.

Rechavi starts with the basics. DNA holds the genetic instructions, and the full set of genes, the genome, is present in every cell of the body. Genes are made of DNA and sit in chromosomes. A chromosome is DNA plus the proteins that condense it, since each cell holds a very large amount of DNA. Huberman compares this to thread wound on a spool.

Rechavi's analogy is an IKEA book kept in every room of a house. The book has instructions for every piece of furniture, but each room only needs certain items. So you take out the page for, say, a chair and use it in the living room. In this picture the genome is the whole book, the page you pull out is the RNA, and the finished chair is the protein. Rechavi adds that this only describes messenger RNA, which is a small share of the RNA in a cell. Less than 2% of the genome encodes messenger RNA. Much of the rest of the genome is transcribed into RNAs that do other jobs. Scientists understand some of these RNAs, and many of them they don't.

Huberman asks about the key exception to "same genes everywhere": the split between somatic cells and germ cells. Rechavi agrees that cell types differ. Leg cells differ from brain cells, and within the brain some cells make dopamine and others make serotonin. The more basic split, though, is between the soma and the germline.

The germ cells are supposed to be the only cells that contribute to the next generation