A week in science: A copper-age "queen," a sea squirt and malaria-fighting mosquitoes
ADRIAN FLORIDO, HOST:
Time now for some science news from our friends at NPR's Short Wave podcast. Regina Barber and Geoff Brumfiel are here now for our science roundup. Hey, you two.
GEOFF BRUMFIEL, BYLINE: Hello.
REGINA BARBER, BYLINE: Hey.
FLORIDO: OK, so as usual, you have brought us three stories this week of science in the news. So give us a tease.
BARBER: So we've got a story about a half-a-billion-year-old sea squirt that might have us rethink when vertebrates came about...
BRUMFIEL: A way to use mosquitoes to fight malaria and a Copper Age Spanish leader.
FLORIDO: OK. So Regina, you go first. Researchers have been studying the fossil of something you called a sea squirt.
BARBER: Yeah. So recently, researchers at Harvard published a paper in Nature Communications detailing a newly identified, super old, very well-preserved species of sea squirt. And if you're like me, you're wondering, what is a sea squirt?
FLORIDO: Yes. I don't know what that is.
BARBER: (Laughter) Yeah, they're a type of small, tube-shaped creature. And they're part of a category of animals called tunicates.
BRUMFIEL: And tunicates - obviously, you know this, Adrian - but just for our audience...
FLORIDO: Yes, obviously.
BRUMFIEL: ...Are very cool. They have this precursor spinal cord. And they're the closest invertebrate relative that we vertebrates have.
BARBER: Yeah, they've been around for half a billion years. But because they're squishy and soft, it's hard to find fossils of them, which means there's almost no traces of it in the fossil record. But recently they found this thing hiding out in the collections vault of the Natural History Museum of Utah in Salt Lake City. I spoke to one of the paleontologists on the paper, Karma Nanglu. He says that this fossil is...
KARMA NANGLU: Essentially the only tunicate in the fossil record that can tell us anything about their early evolution.
FLORIDO: So this thing is a half a billion years old. What does it tell us today?
BARBER: Yeah. So like Geoff said, tunicates and humans share a common ancestor. So this fossil can tell us maybe what that common ancestor looked like, but also tells us that it might be older than we thought.
FLORIDO: But I've got to wonder - do we humans still have anything in common with a sea squirt?
BARBER: Yeah, we do, actually. The soft tissues in modern-day sea squirts share some gene regulatory pathways with the muscles in your heart.
BARBER: So the heart beating in your chest right now is genetically linked in a distant way to this creature from half a billion years ago. And what's even more exciting is Karma Nanglu says that there could be other fossils like this one already in museums, sitting in cabinets, waiting to be found. And that could be like striking gold.
NANGLU: There's definitely gold inside there. And you have to prospect for it kind of like gold. You got to open some of the cabinets that maybe don't sound so exciting, and then sometimes you hit a story like this.
FLORIDO: I can almost imagine the TV show, you know - "The Sea Squirt Hunters."
BARBER: I love it.
FLORIDO: All right. For our second story, let's talk about mosquitoes and the diseases that they help spread, specifically malaria. Geoff, I understand that there is new research that might one day make mosquitoes less prone to carrying that disease.
BRUMFIEL: That's right. Researchers have managed to genetically engineer mosquitoes to produce their own malaria-fighting antibodies. So just to remind everyone, malaria is caused by a parasite. The parasite grows in humans, gets into the blood and makes us really sick. And then mosquitoes carry the parasites from person to person, but it doesn't make the mosquitoes ill.
FLORIDO: OK, wait. Let me just be clear here. The mosquitoes carry all these malaria parasites. But because they don't get sick from that parasite, their immune systems don't bother to fight it?
BRUMFIEL: Until now, that's right. These researchers figured out a way to genetically modify the mosquitoes so that they naturally produced antibodies that fought the malaria parasite. They used technology called CRISPR that lets scientists precisely edit the genetic code of animals. Basically, it puts the insects on the front lines of this disease.
BARBER: OK. So Geoff, I'm going to stop you right there because genetically modifying wild animals can be controversial.
BRUMFIEL: Yeah. In this case, it is absolutely controversial. In fact, our colleague Rob Stein has reported on some other scientists who are working on ways to wipe out mosquitoes altogether, which has really stirred things up. Now, arguably, a good thing about this paper is it doesn't use that sort of gene-editing technology to try and wipe mosquitoes out. Instead, it sort of turns them into allies against malaria. Of course, that also means there's a bunch of genetically modified insects flying around. And environmentalists say the risks of spreading these genes through mosquito populations far outweigh the benefits, especially when there are other technologies that can control malaria.
FLORIDO: And aside from being sort of potentially hugely controversial, I mean, there's just the question of - does this work?
BRUMFIEL: Well, Anthony James of the University of California, Irvine led the study, and he says these little skeeter antibodies do the job pretty well.
ANTHONY JAMES: They work very well. They reduce the number of parasites in the mosquito in - importantly, in the salivary glands, which is where they would be before they're transmitted to a new human host.
BRUMFIEL: According to this paper in the Proceedings of the National Academy of Sciences, they believe that they could reduce malaria by 50- to 90% in some scenarios. But of course, this is still in the early stages. There's a long way to go in terms of regulation and just testing.
FLORIDO: OK. Well, for our final story, we have a surprise from the world of archaeology. And I understand it's from a site, Geoff, in southwest Spain.
BRUMFIEL: Yes. So this goes back to a discovery in 2008. An international team of researchers have reevaluated the remains of a person who was a ruler in the Copper Age.
BARBER: Yeah, and when we're talking about the Copper Age, we're talking about nearly 5,000 years ago.
BRUMFIEL: Yeah. Scientists used to think those remains belonged to a man, but now these researchers think it's more likely they belonged to a woman. They published their findings recently in the journal Scientific Reports.
FLORIDO: And who was this person - some kind of royal?
BRUMFIEL: Well, probably not a king or queen - this was a time before they existed in the world. The researchers think this person was more like a social leader. They were originally nicknamed the Ivory Man because of all the ivory objects found around the burial site, but now they are calling her the Ivory Lady.
FLORIDO: That seems like a pretty dramatic find. Why did it take 15 years to reach this conclusion?
BRUMFIEL: Well, it comes down to the technique the researchers had available. Archaeologists usually determine a skeleton's sex by looking at the pelvis and the skull or by looking at DNA. But when remains are this old, a lot of things get broken down. One thing that does tend to stick around are teeth.
BARBER: And that's because tooth enamel is actually the hardest part of the human body.
BRUMFIEL: So it turns out there's a small protein in tooth enamel that has two different versions - one if you have an X chromosome and one if you have a Y. So if someone is chromosomally female, they'll only have the X version of the protein, not the Y.
FLORIDO: And so I'm guessing that the researchers only saw the X version of this protein in the teeth of these remains and therefore think that it was a female.
BARBER: Yeah, most likely - they didn't see any Y version of this protein. And while it's possible that there might have been low amounts and they weren't detected, the chances of that seem low.
FLORIDO: So what does this mean for how archaeologists think about, you know, society during the Copper Age - 5,000 years ago?
BARBER: Well, it means that women might have held more positions of power in this time than scientists previously thought. One of the scientists involved in this work, Leonardo Garcia Sanjuan, said sometimes the sex of half or more skeletal remains cannot be determined, and this technique could really change that.
FLORIDO: OK. That's Regina Barber and Geoff Brumfiel from NPR's science podcast, Short Wave, where you can learn about new discoveries, everyday mysteries and the science behind the headlines. Regina, Geoff, thanks so much.
BRUMFIEL: Thank you.
BARBER: Thank you.
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