Name: 你是由病毒組成的，你卻無能為力! (You Are Made Of Viruses & There’s Nothing You Can Do About It!)
Uploaded: 2021-01-14T05:34:46.000Z
Duration: 3 min 50 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。學這些英文用法：武漢肺炎,新型冠狀病毒,新冠肺炎,COVID-19

Right now, at this very moment you have a virus controlling your brain.

Fun fact: Our DNA contains a lot of virus DNA. Over one hundred thousand pieces of it!

Over 8% of our DNA is made up of so-called En-dodge-e-nus retroviruses. And a recent

study by Lund University in Sweden indicates that just such a virus might be responsible

This study found that when these virus DNA bits are activated, they also activate nearby

genes. Meaning, old viruses control our brains, well, that there are some old viruses in our

DNA that control when certain genes get switched on and off.

The researchers say this suggests that retroviruses have played an important role in the development

of a complex brain. Perhaps they are one of the reasons brain cells are so complicated

and versatile, giving humans the evolutionary advantage of intelligence.

Well, you can think of them like fossils. Once upon a time, millions of years ago, one

of our ancestors got a virus. Maybe a cold, maybe something else. Back then, the virus

was just a normal retrovirus, hanging out in a host cell. What makes retroviruses unique,

is how they reproduce. Retrovirus carry their genetic material in RNA. To make more copies

of itself, it makes a DNA copy of its genes and inserts it into a host’s DNA. The host

cell then reads the DNA with the viral insert and is tricked into making more copies of

But by a stroke of luck, this particular virus happened to infect a sperm or egg cell, then

when the baby developed from that cell, it carried that virus DNA in every cell in its

body, and when it in turn reproduced, passed that bit of DNA on to its baby. and so and

These bits of viral DNA become so well integrated into the host’s DNA, they become almost

harmless. The viruses mutate to the point they can’t function. They lose their ability

to break out of a cell and infect a new one, eventually, they can only make copies of themselves

which get inserted back into the host cell. Multiple copies of the virus gene can wind

Since this has been going on for quite a while, humans and other mammals have defenses against

these DNA intruders, proteins that keep the virus from replicating. It’s thought that

most of the time this bit of virus DNA in our genome doesn’t do anything. So they

become what scientists consider “junk DNA”

While most of these viral fossils are just DNA duds, sometimes they are harmful. They’ve

been linked to some brain disorders, like schizophrenia and even might cause certain

cancers. Sometimes, they are kind of good.

Some domesticated viral DNA functions like a gene regulator, they can tell which genes

to turn on and off. On occasion the virus DNA is hijacked and put to good use. We owe

a lot of our success to virus DNA - and when I saw “our” I mean mammals. On at least

6 different occasions, virus DNA led to the development of placenta in various mammalian

species, a huge evolutionary step. This viral protein, called syncytin, used to help host

cells bind together so a virus could spread more easily. Now this protein is responsible

for the lining in the placenta that helps aid nutrient exchange between the mother and

developing fetus and protects the fetus from the mom’s immune system. Studies show that

when these viral genes matter a whole lot, when they are turned off in mice, embryos

So we’re a little bit viral.. That’s kind of cool, and researchers think this latest

study could lead to more research on genetic links in certain diseases of the brain. Most

of the research on genetic factors for diseases focus on just two percent of the human genome.

Adding the possibility of a viral related genetic link opens a whole new range of possibilities

so what do you think of our viral inheritance? Cool? Weird? Both? Sound off in the comments

below. and for more cool and weird science, check out DNews everyday.