0:00:04.7
Sarah Crespi: This is the Science Podcast for December 15th, 2023. I’m Sarah Crespi. First up this week it’s Science’s Breakthrough of the Year with producer Meagan Cantwell and news editor Greg Miller and before they get to the tippy top science find, we’ll hear about a few of this year’s runners up. After that a researcher Jen Tinsman joins me to discuss Putting a stop to pangolin Trafficking with Genetics. These scaly little guys are the most trafficked mammals in the world and researchers can now use DNA from their scales to find poaching hotspots.
0:00:39.1
SC: Well, it’s almost the end of the year, which means it’s time for one of science’s longest traditions, which is the Breakthrough of the Year in different fields of science, we highlight a Breakthrough of the Year as well as nine runners up. I’m here with Greg Miller who edited this section this year and we’re gonna talk through some of the highlights. Thank you so much for joining me, Greg.
0:01:00.5
Greg Miller: Glad to be here.
0:01:00.9
SC: So as usual, we’ll save this year’s Breakthrough of the Year for the very last thing that we talk about, but we’re actually gonna go back to the 2016 Breakthrough of the Year, which was when LIGO detected a burst of waves from two star-sized black holes that were merging. But this year’s runner up isn’t about two star sized black holes, it’s about two super massive black holes that are merging together. What do scientists think happen when these two massive objects are colliding and dancing together?
0:01:29.1
GM: Yeah, they are really enormous. These black holes we’re talking about are millions or even billions of times the mass of our sun. When they actually merge, there would be a brief burst of gravitational waves and it’s possible that the resulting giant would recoil and even get flung out of the galaxy altogether. But it’s actually shortly before that point when the two black holes are circling each other in kind of a death spiral, getting closer and closer that they emit steady and powerful gravitational waves. And those are the waves that astronomers are hoping to detect.
0:02:10.4
SC: The detector that they used to pick up on those smaller black holes colliding LIGO, wasn’t quite up to the task of figuring out the signal for these super massive black hole mergers. How were astronomers able to pick up on the signal?
0:02:22.9
GM: The gravitational waves from these super massive black hole binaries have wavelengths that are measured in light years. LIGOs detectors are only a few kilometers long, so they’re way, way, way too small. In this case, astronomers turn to pulsars, which are rapidly spinning stars, kind of burnt out stars that are sending pulses of radio waves in our direction with incredible regularity like an atomic clock. And so by monitoring those pulses for years and years, scientists have detected very slight variations in the pulse arrival times, signifying that gravitational waves have squashed or stretched the space in between the pulsars and earth and altered their arrival time here.
0:03:10.1
SC: Now that they know what this signal might look like from supermassive black holes colliding, can they kind of look at records in the past to figure out if maybe they’ve actually picked up on this signal before?
0:03:20.9
GM: So, so far astronomers have only found a few dozen pulsars that are close enough and regular enough to be used as detectors. But their upcoming radio telescopes like the Square kilometer array, should enable them to find more pulsars and have enough pulsars to map where the gravitational waves are coming from and find galaxies where a titanic clash like this is about to happen.
0:03:47.9
SC: Moving back to our planet. The next runner up is about the potential to fuel our world, and this is centering around natural hydrogen. How did researchers initially find out that this energy source was even available within our earth?
0:04:00.8
GM: There had been hints of this from century old well logs and studies and mines and seeps, but in the ’80s there was a really dramatic demonstration of it in a village in Mali where people were drilling for water and one of their boreholes that they had drilled open to find water turned out to be dry, but there was a wind coming out of it and when one of the workers peered into the hole while smoking a cigarette, the wind caught fire and exploded in his face. He fortunately survived. So when it turned out that the gas was flammable because it was 98% hydrogen. Years later, they managed to hook up the gas to a generator and use it to make electricity, which the village hadn’t had to that point.
0:04:48.1
SC: The discovery of natural hydrogen in that village was made almost decades ago at this point. But this year in particular, natural hydrogen made the runners up because there’s been a lot of money and research put into looking into this energy source more. What are the pressing questions right now that researchers are looking into to see whether this can actually be harnessed and used worldwide?
0:05:06.3
GM: So the big practical questions at this point are whether it’s concentrated in reservoirs that would allow it to be extracted easily enough to make economic sense. So the expected sources for hydrogen are very deep and drilling is expensive. So the question is does it really accumulate in shallow traps like oil and gas do that would make it feasible to extract it? The fact that the earth has these reserves at all is kind of surprising because hydrogen is so reactive. Geologists had assumed that any hydrogen that was locked up in the Earth’s crust would be eaten up by microbes or converted to other compounds.
0:05:49.4
SC: There have been some surveys conducted to try to map where this natural hydrogen is. Do geologists have a sense of exactly how much of it is out there?
0:05:55.9
GM: There’s an upcoming estimate that hasn’t been published yet from the US Geological Survey suggesting that there could be as much as a trillion tons of hydrogen in the earth’s crust, which would mean enough to satisfy global demand for thousands of years.
0:06:14.0
SC: This next discovery is similarly building off of something that we’ve known about for a while, but we’re getting better information on. This has to do with when people first arrived to the Americas for several decades, people thought it was 16,000 years ago, but in 2021 there was a groundbreaking discovery of human footprints that suggested this date could have been much earlier. How were archeologists initially able to tease out when these footprints made their mark?
0:06:41.0
GM: The footprints were left on what was once the muddy shore of an ancient lake in what’s now White Sands National Monument in New Mexico. And the team that found them initially dated them between 21,000 and 23,000 years ago based on radiocarbon dating of seeds from grassy aquatic plants that had been uncovered that once lived in the lake and had been uncovered in the sediment layers around the footprints.
0:07:14.8
SC: When that initial discovery was published, there was some skepticism, not everybody immediately was on board with pushing the people of the Americas back to 21 or 23,000 years ago, but the reason this is a runner up this year is ’cause there’s some new analysis that further support this older date. What did they do this year differently?
0:07:31.6
GM: The skeptics to the initial paper argued that since the plants were growing in the lake, they could have absorbed carbon from ancient sediments dissolved in the lake, which would’ve made the seeds and therefore the footprints seem older than they actually were. This time the team went back and they radiocarbon-dated pollen from land plants that wouldn’t have been able to absorb ancient carbon from the lake. And they also used another method to analyze quartz grains that were embedded in the sediments around the footprints. And they used a different method that measures when the quartz grains last were exposed to light. Those new independent sources, the dates they came up with overlapped almost perfectly with their initial estimate of 21 to 23,000 years ago.
0:08:22.0
SC: What would the implications be for pushing back this date?
0:08:25.3
GM: It would be a huge deal if these dates are correct, the prints were left at the peak of the last ice age when glaciers covered Canada, which means that humans must have made the journey into the Americas before those ice sheets formed rather than after they had melted. So it’s a really big shift in thinking about this chapter of human history.
0:08:47.3
SC: The technology behind this next advance has cracked our list for the top advances in science for the past several years. This ranges from predicting protein structures to mastering poker and of course we’re talking about artificial intelligence here. This year in particular, there were leaps in using AI to predict weather. How exactly is AI’s approach to forecasting different than traditional weather models?
0:09:12.9
GM: AI is definitely on a roll the last few years. With weather forecasting, the traditional method is called numerical weather prediction and it relies on massive computing power to crunch these fluid dynamics equations that describe the atmosphere. So whether agencies run these models on supercomputers and they can take several hours to run which limits how often they can update their forecasts, AI does something entirely different. What AI is really good at in all these cases is finding patterns so researchers can feed it decades worth of weather data and train it to predict future weather patterns based on what’s happened in the past. Once they’ve trained the models, they’re far less computationally intensive. They can run on desktop and crank out forecasts in less than a minute.
0:10:04.3
SC: That’s amazing. And in terms of accuracy, are these AI models on par or exceeding what traditional models can do?
0:10:12.8
GM: They’re already pretty good. In some cases they produce forecasts that are as accurate as the traditional models are even a little better. In one example this summer, Google’s graph cast model predicted where Hurricane Lee in the Atlantic Ocean would make landfall nine days ahead of time, whereas one of the best traditional forecast models could only predict where it would make landfall six days ahead of time. So that’s a pretty significant difference.
0:10:39.1
SC: Even though it is pretty accurate, there’s definitely still room left to growth. What are researchers doing right now to try to improve these AI models and make them even more competitive with traditional models?
0:10:48.2
GM: At this point, the AI models don’t do a great job with certain weather features. So while they’re good at predicting the trajectory of hurricanes for example, they’re not very good at predicting their strength and things like that. We’ll probably improve as researchers refine the models and feed more direct data observations into them to train them. But there might be some built-in limitations to AI because in particular since the AI is trained on past weather data, the patterns it learns might not be as relevant for predicting the weather in a future that’s altered by climate change.
0:11:28.4
SC: Yeah, that’s throwing on a whole other variable that’s probably hard to predict. All right, well great. Those are all the runners up that we’re gonna discuss and if you are interested in learning about the others, you can head to science.org/boty2023 to read about all the other runners up. Some of the other highlights are the first malaria vaccine as well as a new era in super computing. But now we’re switching gears and it’s time to talk about the Breakthrough of the Year. So Greg, what is the Breakthrough of the Year this year?
0:11:55.6
GM: The Breakthrough of the Year, this year is a class of drugs called GLP-1 agonist, which people might know better by some of the brand names like Ozempic and Wegovy. These drugs have been around for quite a few years for treating diabetes and more recently for treating obesity. But this year we got some really good evidence that they can have health benefits beyond weight loss, particularly for cardiovascular health.
0:12:21.3
SC: In the US at least, I feel like I’ve heard Ozempic everywhere all the time, but it definitely wasn’t an overnight success. This is something that has been in the work for decades. Could you talk a little bit about the journey of going from initially isolating this peptide to the very, very effective drugs that we have now?
0:12:39.4
GM: GLP-1 which is short for glucagon like peptide-1, the hormone was discovered in the early ’80s and initially attracted interest for treating diabetes in the early ’90s. But along the way there was starting to be some evidence from animal studies and then some small studies with people that these drugs could also reduce hunger. And so interest started to grow in using them to treat obesity. But one of the obstacles that they faced with some of the early versions of the GLP-1 drugs was that they broke down really quickly in the body. A lot of the early effort went into developing versions with more persistent effects, and now some of the current drugs work with just one injection a week, which is a big difference. At the same time, researchers have also refined the drugs to make them more effective at helping people lose weight. Some of the trials that have come out in the last few years have been reporting people losing 15 to 20% of their body weight over the course of a little more than a year.
0:13:44.0
SC: I feel like the challenge with medicine is always pegging down exactly when the right time is to call it a breakthrough, whether it’s like early trials or now. And I mean, but like you said, the reason that we chose it this year was because of the success in reducing heart attacks and strokes. Could you kind of talk about why that’s so important?
0:14:04.8
GM: It’s important because it shows that these drugs have potential benefits beyond just weight loss. People clearly can carry excess weight and still be healthy, but excess weight and obesity do come with some serious other health risks like diabetes and heart disease. So if you can make a dent in that, it would be a huge deal for public health. And these studies that have come out this year give us really compelling evidence that might be possible.
0:14:33.2
SC: We can switch gears then to moving beyond weight loss. That’s mainly what GLP-1 drugs are used for now, but there’s a whole host of other conditions that scientists are looking into to see if they might help in those cases, what are some of the different applications that scientists are looking into right now?
0:14:47.8
GM: So another interesting development this year was a trial in people with diabetes who also had kidney disease. In October, the company, NOVO Nordisk put out a press release saying that they’d stopped the trial because the results were so clear and positive. And granted, all we have at this point is the company’s word for that. There’s also been a lot of interest in using these drugs to curb addiction. There are a lot of anecdotal reports people may have read in in the media about people taking GLP-1 drugs for obesity or diabetes reporting that they no longer crave alcohol or cigarettes. And there are a number of clinical trials underway now to test whether these drugs can help people with substance abuse disorders and addiction.
0:15:32.2
SC: Well thank you so much Greg for speaking to me.
0:15:34.5
GM: Yeah, thank you.
0:15:35.0
SC: Greg Miller is a contributing editor at Science. You can find links to all the content we talked about and more at science.org/podcast. Up next, researcher Jen Tinsman describes her work mapping out the origins of trafficked pangolin Scales.
0:16:00.4
SC: Pangolins, these scaly tree climbing mammals are native to Asia and Africa, and turns out they’re the most trafficked mammals in the world as their populations have declined in Asia, Africa has now become the main source for pangolin meat for eating and pangolin scales for unproven traditional medicines. This week in science, Jen Tinsman and colleagues describe a genetic approach to tracking illegal pangolin trade routes, and they talk about how genetics sleuthing could be used to slow the flow of pangolin parts. Hi Jen, welcome to the science podcast.
0:16:33.5
Jen Tinsman: Hi Sarah. I’m so happy to be here.
0:16:35.5
SC: That’s great. Okay, so I’ve seen pictures of pangolins, they’re very cute. If you like your mammals scaly, you know, what else should we know about them? Are they big, are they nocturnal? What’s their lifestyle like?
0:16:46.5
JT: So some of them are nocturnal, some of them are a diurnal. So mostly active during the day. There are basically two types of pangolins. There’s the tree pangolins who spend most of their time arboreal. They’re not confined to the trees, but they mostly hang out there eating ants and termites. And then there are ground pangolins who are pretty much terrestrial and they spend time in the forest, in more open habitats, again, looking for ants and termites, which are the main food for all pangolins.
0:17:17.2
SC: And they’re covered in these keratin scales, right? Like fingernails just all over their bodies.
0:17:22.0
JT: Yes, exactly. I call them ugly cute.
0:17:25.9
SC: Yes.
0:17:26.7
JT: I’ve been working on them for so long. I think they’re quite charming, but yeah, they are really strange, strange looking.
0:17:33.4
SC: Very cool. So as I mentioned in my intro, this is the most trafficked mammal. What does that mean? How much is the most? How many are moved per year or you know, what do we know in terms of numbers there?
0:17:45.3
JT: So the, and I’m gonna make a lot of puns, I’m sorry. The scale of trafficking of pangolins is, it’s really wild. Obviously with illegal activity it’s hard to get really solid, precise numbers, but we know from our work that in 2019 the year with the most pangolin trafficking, 250,000 pangolins were shipped from Africa to Asia and interdicted, or caught by law enforcement. Estimates of all the entire wildlife trade in pangolins. So the ones that aren’t caught by law enforcement range from 400,000 African pangolins per year to 2.7 million pangolins per year, which is just an absolutely staggering number. They’re hard to study in the wild. So we don’t have really great population estimates for these guys, but there’s no level of pangolin population that would make that amount of harvest sustainable. So it’s a really urgent threat to all of the eight species of pangolins.
0:18:38.8
SC: Absolutely. I can’t imagine any population sustaining that level of takings. Just a sidebar here a little bit, I guess, why aren’t people farming them or you know, maintaining populations in captivity and using those for these purposes?
0:18:51.5
JT: Pangolins do not thrive in captivity. They’re really hard to keep alive. Like you won’t see them in almost any zoo. If you go to a zoo in the US or elsewhere in the world, they just don’t do well in captivity and they do not breed in captivity. So that’s not a conservation option for any of these species, unfortunately.
0:19:14.0
SC: Yeah. When you did your study here, you were looking at samples of trafficked pangolins and then comparing it to, you know, what we know about where they live in the wild. Where did you get these samples, these trafficked samples? Where did they come from?
0:19:28.9
JT: The trafficked samples were all confiscated by authorities in Hong Kong, SAR in China. And they did a really great job of keeping track of which scales came from which seizure. And they kept data on like what year the seizure was, the weight of the seizure, because what’s most often trafficked from Africa to Asia is just the scales of pangolins and so they’d weigh them. So they had this kind of library of recent pangolin trafficking that was coming into Hong Kong and then presumably bound for retail markets in China and perhaps other locations. So that’s where the confiscated samples came from.
0:20:07.6
SC: And how many did you end up testing or taking data from?
0:20:13.6
JT: We tested about 650 scales, but those scales represented, was it 32 seizures from 2013 to 2018. Those seizures in total weighed about 38 metric tons and they represented over a hundred thousand killed pangolins. So an absolutely staggering number, but also just a drop in the bucket of pangolin trafficking over that time period.
0:20:38.2
SC: Wow. And a method question here, keratin is a protein, it doesn’t necessarily have any DNA in it. So how are you, what information were you able to get out of scales?
0:20:47.8
JT: So it is tricky. You can get DNA out of the scale itself. Human forensics, you know, they can use hair samples or fingernail samples to get DNA out of, it’s just, it’s not a guarantee. Like you might get a scale that’s a dud, but you can drill into the scales and do phenol chloroform extraction and actually get DNA from the scale itself. We ended up getting pretty lucky in that often there would be like a little bit of remnant tissue on the scale. And so that’s what we focused on because that’s a much easier extraction and processing pipeline in lab than actually getting the DNA out of the scale. And unfortunately there are so many trafficked pangolins, it’s not really hard to target the scales that have some remnant tissue on them.
0:21:30.4
SC: In addition to the the traffic samples, you also collected samples from wild pangolins in Africa and you obviously not gonna involve yourself in purchasing pangolins. So how did you get those?
0:21:41.1
JT: The first part of the project, we actually collected samples from wild pangolins with known geographic origins. We didn’t actually interact with any live animals for this study. Pangolins are really sensitive to handling and capture. So the way that we collected samples in the wild was my team of amazing co-authors went to various local like hyper-local rural bush meat markets, or more often they interacted with hunters and requested a sample donation. People are selling these animals out in the open and so typically they’ll have no problem just donating like the tongue or like a little bit of muscle, some part of the animal that’s not too valuable to them. We never compensated anybody for a sample, which tells you how prevalent pangolins are being hunted and being offered for sale in local bush meat markets in Central and West Africa. The other way that we got wild samples to compare those confiscated ones to was recent museum specimens. And so we just kind of cobbled together this sampling representing almost the entire range of white-bellied pangolins in the wild where they’re distributed from Senegal and West Africa down to Zambia in like Central East Africa. So it’s a massive range and massive undertaking, but we got a bunch of wild samples from throughout the range to compare the confiscated ones to.
0:23:05.2
SC: So bringing these two things together, you have a map of kind of the genetic diversity over this very large range of pangolins, and then you have this sample over a number of years of trafficked pangolin. So what did you learn about where they come from, where they go and how that’s changed over time?
0:23:23.3
JT: It was pretty surprising the vast majority of our confiscated samples, so those 650 scales from 2013 to 2018, the vast majority of those guys were coming from pretty much two poaching hotspots along international borders in Central Africa. One, the smaller one was the border between Cameroon and Nigeria, and then the other much larger poaching hotspot that we detected was Cameroon’s southern border with Equatorial Guinea and Gabon. And so that’s just a really tiny geographic area to be producing all of the killed pangolins that were in our confiscated sample. The other really interesting thing that we detected was, even though we just had this sort of brief snapshot window of 2013 to 2018, we found that there were changes in the origins of trafficked pangolins over time. So in 2013, at the beginning of our study, all of the pangolins that we had in that sample were coming from West Africa, and then it slowly shifted over and so by like 2016 and then through 2018, almost all of the pangolins in our sample were coming from those poaching hotspots in Central Africa that I just mentioned.
0:24:36.8
SC: Things are moving and it’s obviously looking back in time. So how can this type of work or this approach be turned into a tool that might help intervene in the illegal trade?
0:24:48.1
JT: I actually, I work for the Fish and Wildlife Service now in the US but this paper was written by academics. So we don’t have access to a current and ongoing law enforcement investigations. The hope for this assay that we made that can localize confiscated samples is that we will get it into the hands of authorities in Hong Kong, for example, who donated the samples to us, and that they will be able to genotype ongoing investigations and get an almost real time assessment of where trafficked pangolins are coming from. So the assay that we built by science standards, it’s pretty quick and cheap. We estimate like once you’ve got everything up and running, it’s six to $10 per sample. It takes less than a week from extracting DNA from the confiscated scale until getting a result. So if we get this operationalized, it can be a pretty quick turnaround for understanding where trafficked white-bellied pangolins are coming from. And so the hope now that this assay is out in the world and published is that it will be of use to people who are actually doing law enforcement and that they’ll turn those data into information for law enforcement officials and conservation professionals in Africa who can then really target hotspots of illegal activity like pangolin poaching in Central Africa.
0:26:05.0
SC: Alright. It’s my understanding from my, my limited reading here that the illegal ivory trade is a lot tougher these days. It’s actually, some of it is because of genetics and other kinds of enforcement tactics and pangolins have kind of become a replacement for the poachers, a new trade, a new source of income, say they turn their attention elsewhere. Do you think that this approach could be used for the next animal that becomes the hot poachable?
0:26:32.3
JT: This work was actually inspired in part by work that had been done on the ivory trade doing very similar estimation of geographic origins for trafficked elephant tusks. So that’s basically the backstory behind this project. And we really have seen an increase in pangolin trafficking. They’ve been getting more attention. The African species were finally listed in society’s appendix one, which is the most protective level for internationally traded species in 2017. So there’s just been some momentum on these guys recently. And we don’t really know what the future holds. My hope is that pangolin trafficking will die down, but we know that when that happens, people who traffic species are often looking for a replacement, like you said. So we don’t know what the next thing will be after pangolins, but these methods could be applied in a similar way to other trafficked species.
0:27:25.4
JT: The other thing that’s cool about this assay is we know from people who have done local survey work that hunters will just opportunistically take anything that they can sell when they encounter it in the forest. So places where there’s pangolin poaching because there’s a lot of hunting activity in the forest, there’s also probably like strong exploitation pressure on other species. Those hotspots are probably not just hotspots for pangolins, they’re also probably hotspots for other species that are subject to human exploitation. So even now we can use the data that we’ve generated to make a conservation plan and target areas where multiple species are threatened.
0:28:04.3
SC: When you did this work you were in academia at UCLA and now you’re at US Fish and Wildlife, what is your job now?
0:28:12.3
JT: Now I am a forensic scientist at the US Fish and Wildlife Service National Forensics Laboratory and I conduct research on wildlife trafficking. So very similar to what I did at UCLA and I also evaluate evidence in suspected wildlife trafficking cases. My casework involves, if there’s a suspected wildlife trafficking crime involving mammals, the special agents in the US Fish and Wildlife Service or the wildlife inspectors can send that to the lab for a species identification. And I’m one of the mammalogist there who handles mammal evidence when it comes into the lab.
0:28:46.1
SC: That is super cool.
0:28:46.8
JT: The work at UCLA really, when you see that much devastation, when you spend your days thinking about how species are being trafficked to extinction, you really wanna do something about it. And I feel like now that I’m at the US Fish and Wildlife Service, I’m pretty involved where the rubber meets the road of actually trying to reduce the amount of wildlife trafficking that happens in the world.
0:29:06.3
SC: Wonderful. Alright. Thank you so much, Jen. Yeah.
0:29:11.0
JT: Thank you, Sarah.
0:29:11.1
SC: Jen Tinsman is a forensic wildlife biologist. She was at UCLA when she worked on this paper, and now she works at the US Fish and Wildlife Service. You can find a link to the paper we discussed at science.org/podcast. And that concludes this edition of the Science Podcast. If you have any comments or suggestions, write to us at science podcast@aaas.org to find us on the podcasting apps, search for Science Magazine, or you can listen to the show on our website, science.org/podcast. This show was edited by me, Sarah Crespi, Kevin McClain and Meagan Cantwell with production help from Podigy. Jeffrey Cook composed the music on behalf of science and its publisher AAAS. Thanks for joining us.
doi:10.1126/science.zk0pw91
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