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

Andrew Huberman (0:00)

Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health and performance.

I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. And now for my discussion with Dr. Oded Rechavi. Oded, thank you so much for being here.

Oded Rechavi (0:22)

Totally my pleasure.

Andrew Huberman (0:23)

Today, what I mainly want to talk about is the incredible questions that you probe in your lab, which are incredibly significant for each and all of our lives. I think most people have a general understanding of what genes are, what RNA is, and so on. But maybe you could explain to people in very basic terms. And I'll just preface all this by saying that I think most people understand that if they have two blue-eyed parents, that there's a higher probability that their offspring will have blue eyes than brown eyes.

But most people generally understand and accept that if they spend part of their life, let's say, studying architecture, that if they have children, that there's no real genetic reason, we assume, that their children would somehow be better at architecture because they contain the knowledge through the DNA of their parents. They might be exposed to it in the home, so-called nature nurture, also nurture in that case, but that they wouldn't inherit knowledge. Today, I'm hoping you can explain to us why eye color but not knowledge is thought to be inherited and the huge landscape of interesting questions that this opens up, including some evidence that contrary to what we might think, certain types of knowledge at the level of cells and systems can be inherited.

Oded Rechavi (1:39)

So DNA is the material, the genetic instructions that is containing every one of our cells. We have the set of genes, containing the entire set is called the genome, and this is present in every cell of our body, the same set of instructions. Genes are made of DNA and chromosomes, that are containing chromosomes. Chromosomes is the DNA and the proteins that condense the DNA, because we have a huge amount of DNA in every cell, if you need to condense it too.

Andrew Huberman (2:07)

So like thread on a spool.

Oded Rechavi (2:09)

Right. Huge amounts that you have to condense.

We have the same genome, the same DNA in every cell in our body. It's good to have an analogy to understand how it works. This is like the Ikea book that you have in every cell in your body, the instructions to make everything that you need in your house. The chairs, the kitchen, the pictures. But in every room, you want something else. So in the kitchen, you want things that fit the kitchen, and in the toilet, you want things that fit the toilet. So you only remove one particular page of instructions, which is the instruction of how to build a chair.

And this you place in the living room, and in the toilet you put in the toilet. So the genome is the instruction to make everything. This is the Ikea book, and in every cell, we take just the instructions to make one particular furniture, and this is the RNA. And then at the end, you build the chair. The chair is the protein. This is true for one particular type of RNA, which is messenger RNA. In fact, this is just a small percent of the RNA in the cell. So we have a very big genome, and less than 2% of it encodes for this messenger RNA. However, a lot of the genome is transcribed to make RNA that does other things. Some of these RNAs we understand, and many of them we don't.

Andrew Huberman (3:24)

I think it's a beautiful description, and IKEA is not a sponsor of the podcast, so it's a totally fair game to use the IKEA catalog as the analogy for DNA, the specific instructions for specific pieces of furniture is the RNA, and the furniture pieces being the proteins that are essentially made from RNA using messenger RNA.

Oded Rechavi (3:42)

Right.

Andrew Huberman (3:43)

Okay. Despite the fact that the same genes are contained in all the cells of the body, is it fair to say that there's basically one very important exception, which is somatic cells versus germ cells?

Would you mind sharing with us what that distinction is?

Oded Rechavi (3:57)

Yes.

Every cell type is different. We have cells in the legs, we have cells in the brain, we have cells that produce dopamine, cells that produce serotonin and so on. But we can make one very important distinction between the somatic cells and the germ cells. The germ cells are supposed to be the only cells that contributes to the next generation, out of which the next generation will be made. So each of us is made just from a combination of a sperm and an egg. These are two types of germ cells. Then they fuse and you get one fertilized egg. Out of this one cell, all the rest of the body will develop. What happens in the soma, which are all the cells that are not the germ cells, should stay in the soma, should not be able to contribute to the next generation. This is very important and it's thought to be one of the main barriers for the inheritance of acquired traits, the inheritance of memory and so on. Because, for example, like the example that you gave with learning architecture, if I learn about architecture, the information is encoded in my brain. And since my brain cells can't transfer information to the sperm and the egg, because the information is supposed to reside in synaptic connections between different neurons, in particular, circuits that developed.