But what, exactly, is spider silk?

Spider silk is almost entirely protein.

But what, exactly, is spider silk?

Spider silk is almost entirely protein.

Cheryl Hayashi The magnificence of spider silk

There are many kinds of spider silk.

There are many kinds of spider silk.

So silk comes out of the spinnerets, and for those of us spider silk biologists, this is what we call the business end of the spider.

So silk comes out of the spinnerets, and for those of us spider silk biologists, this is what we call the business end of the spider.

How does an individual spider make so many kinds of silk?

Inside each spider, there are hundreds of silk glands, sometimes thousands.

How does an individual spider make so many kinds of silk?

Inside each spider, there are hundreds of silk glands, sometimes thousands.

To give you an idea of what a spider silk protein looks like, this is a dragline silk protein, it's just a portion of it, from the black widow spider.

To give you an idea of what a spider silk protein looks like, this is a dragline silk protein, it's just a portion of it, from the black widow spider.

I'm going to spend the rest of my life studying spider silk.

To borrow from the writings of a spider named Charlotte, silk is terrific.

To borrow from the writings of a spider named Charlotte, silk is terrific.

This is a picture of the spinnerets coming out of a spider and the silk being formed from a spider. Isn't that beautiful?

I love when I'm in the laboratory, a new spider silk sequence comes in.

I love when I'm in the laboratory, a new spider silk sequence comes in.

So this means that both spiders and spider silk have been around for 380 million years.

So this means that both spiders and spider silk have been around for 380 million years.

It's short. And on the bottom, this is the repeat sequence for the egg case, or tubuliform silk protein, for the exact same spider. And you can see how dramatically different these silk proteins are so this is sort of the beauty of the diversification of the spider silk gene family.

And you can see how dramatically different these silk proteins are so this is sort of the beauty of the diversification of the spider silk gene family.

These are the two species of spiders for which the vast majority of time and money on synthetic spider silk research has been to replicate their dragline silk proteins.

These are the two species of spiders for which the vast majority of time and money on synthetic spider silk research has been to replicate their dragline silk proteins.

Even fossil spiders can make silk, as we can see from this impression of a spinneret on this fossil spider.

At the top of the screen, you're seeing the repeat unit from the dragline silk of a garden argiope spider.

Even fossil spiders can make silk, as we can see from this impression of a spinneret on this fossil spider.

At the top of the screen, you're seeing the repeat unit from the dragline silk of a garden argiope spider.

Cheryl Hayashi studies spider silk, one of nature's most high performance materials. Each species of spider can make up to 7 very different kinds of silk. How do they do it? Hayashi explains at the DNA level then shows us how this super strong, super flexible material can inspire.

But how about variation among spider species, so looking at one type of silk and looking at different species of spiders?

But how about variation among spider species, so looking at one type of silk and looking at different species of spiders?

This makes testing spider silk really, really easy to do in the laboratory, because we're actually, you know, testing it in air that's exactly the environment that spiders are using their silk proteins.

This makes testing spider silk really, really easy to do in the laboratory, because we're actually, you know, testing it in air that's exactly the environment that spiders are using their silk proteins.

And on the bottom, this is the repeat sequence for the egg case, or tubuliform silk protein, for the exact same spider.

Each of these silk fibers exits from the spigot, and if you were to trace the fiber back into the spider, what you would find is that each spigot connects to its own individual silk gland. A silk gland kind of looks like a sac with a lot of silk proteins stuck inside.

In an orb web weaving spider, you can find seven types of silk glands, and what I have depicted here in this picture,

Each of these silk fibers exits from the spigot, and if you were to trace the fiber back into the spider, what you would find is that each spigot connects to its own individual silk gland.

In an orb web weaving spider, you can find seven types of silk glands, and what I have depicted here in this picture, let's start at the one o'clock position, there's tubuliform silk glands, which are used to make the outer silk of an egg sac.

It's like the spiders are sharing an ancient secret with me, and that's why I'm going to spend the rest of my life studying spider silk.

Nearly all of these proteins can be explained by a single gene family, so this means that the diversity of silk types we see today is encoded by one gene family, so presumably the original spider ancestor made one kind of silk, and over the last 380 million years, that one silk gene has duplicated and then diverged, specialized, over and over and over again, to get the large variety of flavors of spider silks that we have today.

Nearly all of these proteins can be explained by a single gene family, so this means that the diversity of silk types we see today is encoded by one gene family, so presumably the original spider ancestor made one kind of silk, and over the last 380 million years, that one silk gene has duplicated and then diverged, specialized, over and over and over again, to get the large variety of flavors of spider silks that we have today.

Spider