Name: The Viral Dark Matter Inside Your Body
Uploaded: 2020-05-09T18:30:08.000Z
Duration: 6 min 33 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Adverbs of degree

Humans have mapped nearly all of the land on earth,

and sent probes to the planets and beyond.

But there's a whole world that is left largely unexplored...

There's an enormous amount of unidentified microorganisms living

within animals, plants, and even our own bodies.

Take the human gut for example: only about 50% of the microbes are identifiable.

The other 50% don't match to anything that we know about and I would go so far as to

say a substantial fraction of that is what we call “viral dark matter”.

Viral dark matter is the genetic material from viruses that is so different than the

sequences of viruses that we know about, that it can't be detected with most conventional methods.

In astronomy, dark matter is attributed to certain gravitational observations in the

And that's a pretty good analogy for what we're studying here right?

We can't detect it with any of our reference viruses but we know it exists.

It has features that are vaguely like a virus.

Under a microscope, it looks like a virus, but a closer look at the DNA sequence reveals

that it doesn't match anything ever seen before and so scientists can't confirm what

And a lot of it is thought to be yet unidentified viral information.

Hundreds of thousands of unknown viruses probably are covering our bodies, in our intestine,

on our skin, in our mouth and everywhere else.

In fact, viruses are the most abundant biological entity on earth.

Some, called bacteriophages or phages for short, infect bacteria that live in us and

In the same way that fluctuating bacterial populations are important for our health and well-being,

the viruses that infect those bacteria are of importance as well.

And so viruses are undoubtedly essential for life as we know it on the planet and probably

for the persistence of human populations.

But there are challenges with identifying and even categorizing some of them as viruses.

They're so genetically diverse that two similar looking viruses from the same family,

might actually have almost nothing in common.

There's an interesting term called polyphyletic, which means, for example, children might want

to put whales and say fish into the same category.

But from the perspective of evolution, it's very clear that say fish and whales represent

distinct forms of life that have come to look similar to each other through various sorts of forces.

It may very well be that some of these different viral forms of life are not related to each

other, in which case even using the word virus to link them all together might in some ways

But identifying and classifying this stuff could help us understand the cause of certain

cancers, infections, and even prevent a pandemic.

We have learned, for example, that a range of cancers are caused by previously unknown

transmissible agents, whether it be cervical cancer, the vast majority of which is caused

It's also the case for certain gastric cancers, stomach cancers.

As we start to uncover the diversity of living things that have the potential to infect us,

or perhaps even more likely the sort of bacteria that are so profoundly important in our microbiome,

we have the capacity of identifying agents that perhaps cause chronic diseases.

And that's exactly what researchers at the National Cancer Institute have done.

They were able to catalogue thousands of new viruses in hopes of aiding human health.

At first, the team sampled humans and animals in hopes of understanding two specific families

of viruses that are associated with cancer.

But as they isolated these viruses, they uncovered many more DNA sequences that hadn't been

This is kind of where all labs are at this point.

We go fishing for the things that we like.

And then we get this giant pile of other things.

And it's not possible for one person to hand curate 5000 entities.

Instead of just ignoring these new DNA sequences, they developed software that makes sharing

Called Cenote-Taker, which is freely available online for others to use, it can automatically

annotate virus DNA in a way that's compliant with public databases, making understanding

data and sharing findings easier than ever.

And now that our tool's available, they can easily take their virus genomes, curate

them and annotate them and share them easily with all the other researchers.

And so then, God forbid there is another outbreak or pandemic, it's gonna be easy for researchers

to find that sequence in humans to know exactly where it was previously... in which animals.

We're hoping that basically by rendering the dark matter visible, it just makes it so that

if there's a disease association, somebody is going to see it rather than just ignoring it.

Although these additional viruses are a small fraction of the millions of unknown viruses

that are thought to exist, adding to databases that virologists share is a small step towards

I think it's quite exciting that there is so much that is unknown.

Understanding these things has a deep capacity to help us understand our origins, the nature

of what life is, the diversity of forms that life can exist in, and to help place us in

the broader context of what it means to be alive and what our place in living world