Humans have mapped nearly all of the land
on earth,
explored the deepest oceans,
stepped foot on the moon,
and sent probes to the planets and beyond.
But there’s a whole world that is left largely
unexplored...
the microbial world.
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
cosmos, like the formation of galaxies.
But so far, it can’t be detected.
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.
We can see it.
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
it is or what it does.
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.
More than all other organisms combined.
But most of them are harmless.
Some, called bacteriophages or phages for
short, infect bacteria that live in us and
can actually be good for your health.
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
be misclassification.
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
by human human papilloma virus, HPV.
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
recorded before – viral dark matter.
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
new viral DNA information easier.
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
preventing and treating health issues.
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
really means.
