Ancient Human Relatives At The Top Of The World

8:44 minutes

A brownish jawbone with two teeth from the ancient human relative denisovan on a black background
The Xiahe mandible. Credit: Dongju Zhang, Lanzhou University.

Back in 2008, paleoanthropologists exploring a Siberian cave found one hominid finger bone. DNA analysis of that bone led researchers to announce the discovery of a new kind of hominin, a lineage separate from Neanderthals and Homo sapiens. That hominid lineage became known as the Denisovans, after the cave where the fingerbone was found.

This week, researchers announced another Denisovan find—a jawbone high up on the Tibetan plateau, far away from the 2008 discovery site in Siberia. The find indicates that the Denisovans may have been more widespread than originally thought and may point to the source of genetic adaptations that some modern people have for high-altitude living. Maggie Koerth-Baker, senior science reporter at FiveThirtyEight, joins Ira to discuss the find and other stories from the week in science in this week’s News Roundup, including a company selling NASA faulty aluminum, news about the expansion of the universe, and advances in transplant organ delivery via drone.

Further Reading

  • Learn more about the Denisovans in this Science Friday interview.
  • Read about the company selling NASA faulty aluminum at CNet.

Segment Guests

Maggie Koerth

Maggie Koerth is a science journalist based in Minneapolis, Minnesota.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. A bit later in the hour, some digital estate planning and how one US company is planning for the potential havoc wrought by climate change. But first, back in 2008, paleoanthropologists exploring in a Siberian cave found a single hominid finger bone. DNA analysis of that bone led researchers to say the find marked the discovery of a new kind of ancient human lineage separate from Neanderthals and Homo sapiens. That lineage became known Denisovans after the cave where the finger bone was found. 

This week, researchers announced another Denisovan find far away from the original site. Joining me, now, to talk about why that is important, and other stories from the week in science, is Maggie Koerth-Baker, a senior science reporter at FiveThirtyEight. Nice to have you back again, Maggie. 

MAGGIE KOERTH-BAKER: Thanks for having me. 

IRA FLATOW: Now, tell us about this bone. What’s important about this new bone find? 

MAGGIE KOERTH-BAKER: Well, so the interesting thing about the Denisovan species is that it’s really been something that we know primarily through DNA analysis. So scientists can tell you a lot about this genome, but not about what Denisovans looked like. So the available data really increased significantly this week with this jaw bone find. You know, it tells us a little bit more about their appearance because it lacks a chin, for instance, and has these particularly big teeth that are different in shape and size from those of Neanderthals and modern humans and really any other known hominids. 

And the other thing that’s really important about this is that finding this jaw bone in Tibet helps back up this previous DNA research that had found that a mutation that’s common in modern Tibetans probably originally came from Denisovans. So this mutation is interesting. It’s associated with making it easier to breathe at high altitude. And this 160,000-year-old jawbone shows that the Denisovans where there, living in the Himalayas, at least 120,000 years before Homo sapiens. And they were adapting to their environment in a way that they’d eventually pass on to us. 

IRA FLATOW: And that was 1,500 miles away from the original find. Isn’t that significant? 

MAGGIE KOERTH-BAKER: Right. Yeah, that definitely is also. It means that they were spread out over a pretty big chunk of Asia. 

IRA FLATOW: Mm-hmm. OK, let’s move on to news this week about a scandal involving aluminum for rockets? 

MAGGIE KOERTH-BAKER: Yeah. So at least two unmanned missions to space failed because a NASA contractor was falsifying the results of materials testing. This Justice Department investigation just got published that found that this aluminum extrusion company had deliberately altered certification test results between 1996 and 2015, trying to make it look like the materials it produced met NASA specifications, when they didn’t. And the scam resulted in two satellites failing to reach orbit. Ironically, because they failed to fail, rather than failing themselves. 

So, like, these were things that were part of the payload fairing, which is kind of like this clamshell-shaped housing that protects the satellite during launch. It’s supposed to– 

IRA FLATOW: That opens up and lets it out, right? 


IRA FLATOW: It’s supposed open up. 

MAGGIE KOERTH-BAKER: It’s supposed to separate and fall away. And in both of these launches, it did not separate and fall away, which meant that the rocket weighed too much. And then, the whole thing fell back to Earth and disintegrated. 

And it effectively wasted about $700 million. You know, this is something that the Justice Department and NASA have been investigating for a long time. The company involved got banned from government contracting back in 2015, but this is just the first time the results have been made public. 

IRA FLATOW: It sounds pretty interesting. Let’s move on to a story that we covered a few weeks ago. We talked with astronomer Adam Riess about attempts to measure the Hubble Constant. It seems to be really– a lot of that going on in the news. 

MAGGIE KOERTH-BAKER: Yeah. So the Hubble Constant is kind of an interesting thing. It’s this idea of trying to get a hold of the rate of expansion of the universe. And it is one of the key tasks that was proposed for the Hubble Space Telescope back when it first launched in 1990. 

So over time, the Hubble Space Telescope has been using these observations of the distance between certain kinds of pulsating stars to narrow down its estimate of what this Hubble Constant is, and get a little bit closer and closer to what we assume is an accurate number. They had– what happened this week is that they came out with a new revised estimate. And this one, they think, is narrowing that uncertainty to the point that it’s probably accurate to within 1.9%. But– 


MAGGIE KOERTH-BAKER: I think this is something you guys talked about– 


MAGGIE KOERTH-BAKER: –before. There’s another way to measure the Hubble Constant. And that other way is studying the cosmic microwave background radiation. So essentially, like the leftovers of the Big Bang. 


MAGGIE KOERTH-BAKER: And that’s produced an entirely different estimate of the Hubble Constant. And this new constant that the space telescope researchers think is the most accurate one they’ve ever produced, is now 9% faster than the Constant as measured by that cosmic microwave background radiation. So we’ve got this pretty big difference. 

IRA FLATOW: Wow. And that would make the universe, what, younger, if it’s right? 


IRA FLATOW: Or older or something. 

MAGGIE KOERTH-BAKER: Or both at the same time. I don’t know. Let’s look at our hands and just, like, be fascinated with the universe. But, you know– 

IRA FLATOW: But could they both be right? I mean, could there be new physics, here? Adam Riess said it to us, well, maybe there’s new physics we don’t know about. Maybe we’re both right. You know? 

MAGGIE KOERTH-BAKER: Right. I mean, like, that’s the really interesting thing is the existing cosmological models suggest that these two things, you know, should match. But nobody knows yet why they don’t. So maybe somebody’s got something wrong or maybe what we have wrong is our cosmological models. 



IRA FLATOW: I can’t do good Twilight Zone music. Finally, there’s a story about a delivery system for transplanted organs. Tell us about that. 

MAGGIE KOERTH-BAKER: Yeah, so a lifesaving kidney made a three mile journey from donor to transplant recipient via drone this week. And that is a first for organ transplants. It’s part of a test case demonstration at the University of Maryland. But the researchers are hoping the technology could someday make organ delivery faster and give doctors a better ability to sort of track the movement of the organ in transit. So they would know exactly where it is at all times. 

And that matters for a couple of reasons. First, because those organs lose viability the longer it takes to get to a recipient. But another part, here, is that the organ donor system is currently undergoing some big changes that are likely going to make longer distance transplants more common. 

This is something I read about at FiveThirtyEight a couple of weeks ago, these new rules for liver donations took effect this week. And they are aiming to redistribute organs from parts of the country that have more donor organs to parts that have fewer donor organs. 

And they’re pretty controversial rules. So the State of Kansas is currently considering a bill that would keep Kansas organs for Kansans, for instance. And kidneys are probably the next thing on the list that’s going to get these rule revisions after the liver ones have taken effect. So we could, someday, be looking at a future where somebody in New York City is getting a new organ from rural Pennsylvania delivered via drone. 

IRA FLATOW: Wow. And I guess you really have to have great confidence in a drone’s ability to do this, right? This in not just– you know, it’s not a loaf of bread you’re delivering here. 

MAGGIE KOERTH-BAKER: Right. I mean, like, obviously, there’s a lot of testing to go before people are going to feel as comfortable doing long distance trips with these things. But they were done using multiple pilots following this thing very closely. And as the researchers pointed out, in some ways, it’s a little bit better than sending it in a truck or a plane because you know exactly where the thing is. It’s a lot more easy to track it as it’s moving. 

IRA FLATOW: Could we– could we have an organ donor war break out between the states here? 

MAGGIE KOERTH-BAKER: Well, we could that is– that whole bit is a whole issue in and of itself, where what you have is some parts of the country have higher rates of donor registration and some parts of the country have higher rates of donor need. And those do not necessarily match up real well. 

IRA FLATOW: Maggie Koerth-Baker, Senior Science Reporter, FiveThirtyEight. Always a pleasure to have you. Thanks for joining us. 

MAGGIE KOERTH-BAKER: Thank you for having.

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