Dr. David Sinclair

So that should come apart, right?

So I ripped the rung of the ladder apart.

And that is called a base on the DNA.

And it always matches with its corresponding chemical.

So this shorthand we'd call an A, it always matches with a T. So an AT becomes a rung on the ladder.

And down here, different color.

Here I'm looking at a red and a green step.

Rip it apart.

this is a G and a C letter.

G's and C's come together.

And actually, if I rip this ladder into halves and each step becomes half a ladder, now you can see that you can copy DNA because the A has to match with the T, wrong, and the G has to match with the C. So that's basic DNA.

That's how the information is transferred from cell to cell, from mother to

daughter, our parents to offspring.

There are about 20,000 genes, about 15,000 are turned on, but a different set gets turned on in large part to make a nerve cell compared to a liver cell and a skin cell.

That's gene expression.

And what controls that gene expression is what's called not the genome, which is what's in front of me here on the DNA molecule.

It's the epigenome.

The epigenome is the information we get transferred from cell to cell, from parent to offspring, that's not in this molecule.

So where's this epigenetic information?

Well, it controls which genes are switched on and off.