Where Did Viruses Come From?

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There are fossils of viruses, of sorts, preserved in the DNA of the hosts that they’ve infected. Including you. This molecular fossil trail can help us understand where viruses came from, how they evolved and it can even help us tackle the biggest question of all: Are viruses alive?

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[aideniridescence]

Can't believe these things evolved to also infect computers.

[samvimes]

I've always found the argument over whether viruses are alive or not to be fascinating. It almost becomes a philosophical question, rather than a purely scientific one.

[alexiswoodberry]

Virus: * slaps roof of *human* *
Virus: you can fit so much *pain and suffering* in here

[moonboy]

Some viruses can cause extremely complex results. Eg the rabies virus makes saliva build up in the mouth (so it can be transferred to a new host), makes the host hydrophobic (fear of water means the salvia isn’t being washed away), and makes the host aggressive (likely to bite and spread the virus in the saliva). This is done once the virus becomes established in the host’s brain. Pretty insane.

[VaradMahashabde]

Why isn't this trending? This is VIRAL

[mixey]

When you're in isolation and watching videos about why you are in isolation

[DontHatemusiK]

"over time the relationship became more parasitic... Which sometimes
*like*

[rmar]

Would love to see a video about viruses that have actually caused beneficial mutations in their host.

[Acsabi]

Hey! I'm a molecular biologist, my field of expertise being early evolution and synthetic DNA constructs. Just wanted to say that I'm glad to see you did your homework well and explained all the more important aspects and theories behind viral evolution, and in an easy-to-understand way too. I myself believe the emergent complexity theory is right, maybe because I used to do a lot of research on really simple insertion elements (very basic DNA sequences that emerge in bacterial genomes and can jump around in DNA). and the way they enable more complex DNA constructs to evolve. As to wether viri are alive - Tough question. On one hand they lack a lot of key features that we define as life. On the other hand, they show behavior associated with advanced life, such as assessing their enviroment and making decisions based on their conditions. Anyway, congrats to your video, it was a treat to watch!

[chocothun]

A virus being a vine around the tree of life...makes so much sense.

[yeahoh]

Are viruses alive?
"Well yes, but actually no".

[Tsotha]

that was a lot of information about viruses I have either forgotten since school or never heard until now, many thanks for this video PBS Eons!

[andread]

Are viruses alive?
"Yesn't"

[danstiver]

This was explained really well. If you try looking it up online, you’re more than likely going to find more complicated and harder to understand information on this topic, written for people who are already familiar with the basics in this field.

[Scipio-Africannabis]

Whoever writes this show deserves a raise.

[honortruth]

In order to cause a widespread genetic impact on various species/kinds, viruses didn't necessarily have to immediately mutate the reproductive cells of a common evolutionary ancestor.

While no other altered cells could pass their mutations down to offspring, specific viruses which caused the mutations and who populate the bodies of their hosts without triggering immune response, or in triggering a survivable immune response, can be passed to offspring, as well as to other species/kinds sharing the same habitat. The communicable virus can then cause similar mutations in the new hosts, eventually spreading the mutations into reproductive cells.

In other words, a viral mutation could plausibly leap between reproductively incompatible mammals.

[taniwha]

I like this guy, he's so entertaining and doesn't waste time, plus talks with this sort of humour. I don't know what to call it. But it makes me smile.

[sawyerk]

"Damn, viruses are scary"

Prions: Hold my beer

[crescent_foxx]

Ah YouTube, how smart of you to recommend this to us during a pandemic. This video was actually very interesting though.

[Artie-gcoj]

Very good explanation..I am 65 from Thailand, if i listen to you 50 years ago i would be expertise in this field.

Thank you.