Dr. David Sinclair

Male, female.

And the hallmark of a yeast cell that's old is it loses its A and alpha identity and gets an identity crisis.

It doesn't know what sex it is, and it doesn't mate anymore.

It becomes sterile.

So when I arrived at MIT in 1995, we knew that the hallmark of an old yeast cell, besides it being a bit slow and bigger, is that it became sterile.

It had an identity crisis.

So we figured out that broken chromosomes

distract the sirtuin defenses, and that causes aging in a yeast cell.

But we didn't know in the 90s that that was going to be true for us as well.

It took another decade or two to figure that out.

Yeah.

So sirtuins are proteins that actually are attracted to DNA.

They actually associate with it and they protect the DNA from getting damaged.

Yeah, and they repair broken chromosomes, right?

It's all coming together now.

But they also get distracted.

So look, a sirtuin's normal job, if there's no crisis, is that they turn genes on and off.

They are epigenetic regulators.

They control the epigenome.

They tell a cell what type it is, nerve cell, skin cell, right?