from the world's big
Are We Part Flu?
Carl Zimmer is a science writer, lecturer, and frequent guest on such radio programs as Fresh Air and This American Life. His books include "Soul Made Flesh," "Evolution: The Triumph of an Idea," and "Parasite Rex." In addition to writing books, Zimmer contributes articles to The New York Times, as well as magazines including National Geographic, Time, Scientific American, Science, and Popular Science. He also writes an award-winning blog, The Loom. From 1994 to 1998 Zimmer was a senior editor at Discover, where he remains a contributing editor and writes a monthly column about the brain.
Zimmer is a lecturer at Yale University, where he teaches writing about science and the environment. He is also the first Visiting Scholar at the Science, Health, and Environment Reporting Program at New York University’s Arthur L. Carter Journalism Institute.
Zimmer is a Big Think Delphi Fellow.
Question: Can beneficial viruses be transmitted through the human genome?
Carl Zimmer: Well it’s just been recently that scientists have realized that actually viruses don’t just make us sick. They can actually sometimes end up in our genomes. In other words a virus sort of pastes itself into our own DNA and if that DNA happens to be in an egg or a sperm cell it can get carried down to the next generation, so that virus DNA goes along with our own DNA and it’s in our kids and this happens actually incredibly often, maybe not to everybody in every generation, but if you go over millions and millions of years it actually happens so often that we now have maybe 100,000 pieces of virus DNA in our genome and if you add it all up it’s huge, so about 1.2% of the human genome is made up of genes, things that encode for proteins, the stuff that we consider us. There is about 8.3% that’s a virus. In other words we’re probably about seven times more virus than we are human genes, which is kind of a weird way to thinking about yourself, so if you’re looking for your own idea of your own identity you know the human genome may not be the best place to look for it. You’re just looking at a bunch of viruses.
Now a lot of those viruses, once they get into the genome and they go down through generation after generation they mutate, the get crippled, they can’t make new copies of themselves after awhile and then after awhile a lot of them are just dead. They’re just sort of filler, but there are some cases where our own genomes over millions of years have actually domesticated some of this virus DNA, so what happens is that there is a mutation to one of these virus genes and it starts to switch on and actually make proteins that we can use. So for example ironically there are some proteins from viruses that will help cells defend against invading viruses, so we basically are taking these viruses in and we’re using them as kind of guard dogs to keep the wolves out because they will make proteins that will block receptors that these viruses might use to invade our cells. Another way that viruses have become a part of us is when we’re all embryos in the womb. Before we were born we were sitting inside our mothers and there was this nice placenta that was giving us food. The attachment where the placenta connects to the mother’s body in the uterus has some very special proteins that create the right kind of barrier to support the placenta there and they’re essential. They’re called centisan, and these proteins come from viruses. If you knock those virus genes out, say in a mouse, in an experiment that mouse cannot have babies. Its placenta won’t develop properly. So we really depend on viruses for our complete survival.
Question: What new discoveries are emerging from the study of viruses in the genome?
Carl Zimmer: Okay. Let’s see. So one of the big challenges now is to figure out just how many viruses there really are in the human genome. So far the estimate is 8.3% of our genome is virus, but it actually could be a lot higher. The problem is that over millions of years the viruses in our genome mutate more and more so the look less and less and less recognizable as viruses and so if there was a virus that infected our pre mammal ancestors like 250 million years ago, which it probably did, we can’t see it because it just looks totally random now. So it’s hard to work back that far in time. Our view of things gets fuzzy. I mean that’s true of evolution in general and so it’s also true of this fossil virus record, but the surprising thing is that a lot of different viruses can get into our genome and that’s actually a big surprise. It used to be thought that only a certain kind of virus could get into our genome and it’s called a retrovirus and that’s a virus that might be HIV for example. That’s an example of a retrovirus and all these retroviruses replicate in the same way and what they do is they make copies of their genes and insert them into our DNA, so they actually splice them in there and then our cells churn out all these new viruses and then the cell dies and the viruses go and infect other cells, so that is retroviruses and so you could see how a virus could get into your genome. I mean that is what they do in general, so if they just happen to get trapped in there and then get passed onto the generation you get viruses in the genome.
But now it turns out that you can get other viruses in the genome, so for example, the first non retrovirus that scientists have found in our genome is something called Borna virus and this is actually very weird. So Borna viruses, you probably haven’t heard of them. The reason is that they may or may not infect people. They mostly are known in mammals, so for example they can make horses sick. They get into these horses brains and they do really weird things. The horses go running around in circles or they might bang their head against the wall of their stall until actually they crack their skulls or they starve themselves. It’s really horrendous and some people have actually suggested that schizophrenia and some other psychiatric diseases might be connected to Borna virus, but it’s still very mysterious and controversial. So Borna virus is not a retrovirus. It doesn’t actually insert its own genes into our cells. What it does is just hangs out near our DNA and uses some of the molecular machinery to copy itself. That’s how it works. Well it turns out that there is Borna virus in our DNA. We have Borna virus genes. We’re part Borna virus, which is weird, but apparently our cells and our genomes in a weird way might actually be grabbing these viruses, grabbing genetic material from the viruses that are infecting it and pulling them into their own genome. So we may be sucking in all sorts of viruses and we really don’t know the full range of them. Maybe we’ve got flu virus inside of us. That’s a possibility. Maybe we’re part flu.
Recorded on January 6, 2010
Interviewed by Austin Allen
Everyone knows we have hereditary viruses in our genome. What scientists are just learning is how many there are—and how many we've come to depend on.
Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.
Health officials in China reported that a man was infected with bubonic plague, the infectious disease that caused the Black Death.
- The case was reported in the city of Bayannur, which has issued a level-three plague prevention warning.
- Modern antibiotics can effectively treat bubonic plague, which spreads mainly by fleas.
- Chinese health officials are also monitoring a newly discovered type of swine flu that has the potential to develop into a pandemic virus.
Bacteria under microscope
needpix.com<p>Today, bubonic plague can be treated effectively with antibiotics.</p><p style="margin-left: 20px;">"Unlike in the 14th century, we now have an understanding of how this disease is transmitted," Dr. Shanthi Kappagoda, an infectious disease physician at Stanford Health Care, told <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">Healthline</a>. "We know how to prevent it — avoid handling sick or dead animals in areas where there is transmission. We are also able to treat patients who are infected with effective antibiotics, and can give antibiotics to people who may have been exposed to the bacteria [and] prevent them [from] getting sick."</p>
This plague patient is displaying a swollen, ruptured inguinal lymph node, or buboe.
Centers for Disease Control and Prevention<p>Still, hundreds of people develop bubonic plague every year. In the U.S., a handful of cases occur annually, particularly in New Mexico, Arizona and Colorado, <a href="https://www.cdc.gov/plague/faq/index.html" target="_blank">where habitats allow the bacteria to spread more easily among wild rodent populations</a>. But these cases are very rare, mainly because you need to be in close contact with rodents in order to get infected. And though plague can spread from human to human, this <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">only occurs with pneumonic plague</a>, and transmission is also rare.</p>
A new swine flu in China<p>Last week, researchers in China also reported another public health concern: a new virus that has "all the essential hallmarks" of a pandemic virus.<br></p><p>In a paper published in the <a href="https://www.pnas.org/content/early/2020/06/23/1921186117" target="_blank">Proceedings of the National Academy of Sciences</a>, researchers say the virus was discovered in pigs in China, and it descended from the H1N1 virus, commonly called "swine flu." That virus was able to transmit from human to human, and it killed an estimated 151,700 to 575,400 people worldwide from 2009 to 2010, according to the Centers for Disease Control and Prevention.</p>There's no evidence showing that the new virus can spread from person to person. But the researchers did find that 10 percent of swine workers had been infected by the virus, called G4 reassortant EA H1N1. This level of infectivity raises concerns, because it "greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses," the researchers wrote.
The word "learning" opens up space for more people, places, and ideas.
- The terms 'education' and 'learning' are often used interchangeably, but there is a cultural connotation to the former that can be limiting. Education naturally links to schooling, which is only one form of learning.
- Gregg Behr, founder and co-chair of Remake Learning, believes that this small word shift opens up the possibilities in terms of how and where learning can happen. It also becomes a more inclusive practice, welcoming in a larger, more diverse group of thinkers.
- Post-COVID, the way we think about what learning looks like will inevitably change, so it's crucial to adjust and begin building the necessary support systems today.
Scientists uncovered the secrets of what drove some of the world's last remaining woolly mammoths to extinction.
Every summer, children on the Alaskan island of St Paul cool down in Lake Hill, a crater lake in an extinct volcano – unaware of the mysteries that lie beneath.
The coronavirus pandemic has brought out the perception of selfishness among many.
- Selfish behavior has been analyzed by philosophers and psychologists for centuries.
- New research shows people may be wired for altruistic behavior and get more benefits from it.
- Times of crisis tend to increase self-centered acts.