Dr. David Sinclair

And a major regulator of that process is

is the modification of these steps on the DNA.

These chemicals, the C, particularly the C, which I'm showing you here in this red part of the molecule, the C gets a little chemical added to it called a methyl.

And a methyl is just, if you remember from chemistry high school, it's a carbon with three hydrogens.

It's a very simple molecule.

It gets stuck on that piece of the DNA molecule.

That's called DNA methylation.

And that will help determine, that pattern of DNA methylation determines whether this particular gene will be switched on, say to make an optic nerve, or switched off so that

It becomes a liver cell.

And that happens as we're in the womb and we become an embryo.

And that's the epigenome.

These chemicals that turn genes on and off is the epigenome.

And the information theory of ageing states...

that the information that's in a cell, which includes the DNA, but actually more importantly for aging, is the control systems, the epigenome.

That is pristine when we're young, but as we get older, we lose that epigenetic information.

The ability to tell a cell to be a nerve cell versus a liver cell versus a skin cell, it starts to get erased.

So when we look at a mouse or an old tissue, if I took maybe not your skin, but my skin,

My skin cells are no longer as skin-like as they once were.

They've started to lose their identity.

They're starting actually to look more like nerve cells, and nerve cells are starting to look more like skin cells.