Placeholder Image

Subtitles section Play video

  • The current pandemic has highlighted how important

  • it is for us to know what viruses may be lurking out there.

  • But while we keep one wary eye out for those potentially harmful ones, we're also uncovering

  • just how much viruses have actually shaped humansand the rest of life on Earthin

  • some really surprising ways.

  • 'Virus hunters', as they're known, are

  • scientists who search the hidden corners of the world for viruses that are poised to become

  • human pathogens. In many cases, they're searching for Disease

  • X. That's not the name of an actual illnessit's what we call the hypothetical infection that

  • could cause the next big global disease. The idea is to find it before it finds us.

  • But other researchers are delving into what else viruses are doing on our planet besides

  • making people sick. It's estimated that there are about this many individual viruses

  • on our planet.

  • And we've only made the most miniscule dent

  • in that number: we've found and classified about 9,000 of the viruses on Earth.

  • And of those, only about 200 are known to cause disease in humans.

  • But over the past decade, scientists have been identifying new viruses by the thousands.

  • And the main tool they're using to do metagenomics.

  • This is actually something I'm using in my own research on bacterial communities,

  • so let's break it down together.!

  • In metagenomic sequencing, we take a samplethat

  • can be soil, ocean water, a bodily fluidand we purify it down to the genetic material

  • of just the stuff we're looking for. In this case, let's say it's viruses.

  • So now we have the genomes of all the viruses in our sample. Lets picture each virus's genome

  • as a piece of paper with sentences on it.

  • Because the next stepand this sounds nutsis that we rip each

  • piece of paper up into little strips with just sentences on them.

  • We do this because our sequencing

  • machine has to 'read' all of these genomes.

  • And, if you can picture, it's much faster for lots of people to each read a sentence.

  • And they can each read their sentence at the same time a sentence

  • than it is for one person to read a whole page, one at a time.

  • That's what we're doing

  • when we divide our genome up into little chunks. Now that we've read the sentences in a super

  • efficient way, we can put the sentences back together into the full page, or the full genome.

  • Then we compare that to a library full of known genomes.

  • So we can say, 'this unknown page is the same as this known page that we have on file'.

  • It's a match! We've ID'ed the virus in our sample.

  • And we do this for every virus in our sample.

  • Metagenomic sequencing is an

  • incredibly useful tool that lets us identify huge numbers of microbes really fast.

  • And as scientists have turned that powerful lens on our world to catalogue viruses...they've

  • been astonished at just how many they're finding, everywhere. In the ocean, in our

  • wastewater, inside the spiders in our gardens and of course, inside us. Most of them are

  • totally harmless to humans, and many of them are totally new to science!

  • The viruses in the ocean? They're preying on other marine microorganisms, releasing

  • nutrients. This may be the bottommost foundation of the ocean's food web.

  • The viruses in every ecosystem? They help maintain our planet's biodiversity by keeping

  • other species in check. If viruses suddenly vanished from the planet, it's likely that

  • the balance of other organisms would rapidly get out of whack.

  • And one other major result of all this sequencing is a new understanding of just how thoroughly

  • viruses have shaped life on Earth as we know it.

  • Because they invade living cells to replicate, they're equipped to take over a host's

  • genetic replication machinerysometimes, viral genetic material gets incorporated into

  • the host's. It's estimated that around 8% of human DNA actually came from a virus,

  • including some of our most important skills. Like, the ability of modern humans to give

  • birth probably came from a piece of viral genetic code that jumped over to its mammalian

  • host about 130 million years ago. That gave us our ability to grow a placenta. So, yep.

  • We got hacked, and it's probably the reason we don't lay eggs.

  • Scientists don't know how many more viruses are out there, waiting to be discovered. And

  • of those, we have no idea how many of them may be harmful to us.

  • But sequencing at least some of those nonillion viruses out there is the first step. The next

  • step is to identify what they're living inside...and how exactly these tiny, invisible

  • puppeteers are pulling the strings of our natural world.

  • If you want more on just how many viruses are in our oceans and what they're doing

  • there, you can check out this video, and leave us a comment down below if there's another

  • viral topic you'd like to see us cover. Keep coming back to Seeker for all your microbial

  • updates and as always, thanks for watching. I'll see ya next time.

The current pandemic has highlighted how important

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B1 sequencing genetic sample genome page ocean

Viruses Have Shaped Life on Earth as We Know It, Here’s How

  • 13 1
    Summer posted on 2021/09/27
Video vocabulary