Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, an early ape offers a glimpse of how walking on two feet might have evolved…

Host: Shamini Bundell

How science might need to change in the next 150 years…

Host: Benjamin Thompson

And the bottlenecks for vaccine development. I’m Benjamin Thompson.

Host: Shamini Bundell

And I’m Shamini Bundell.

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Host: Shamini Bundell

First up, one of the defining characteristics of humans, unlike our other great ape cousins, is that we are fully bipedal – we walk upright on two legs. But exactly when and how our species evolved to stand on its own two feet isn’t very clear. This week, scientists report the discovery of an ape fossil that moved around in a way that hasn’t been seen before, and which could shed some light on how humans began to take their first steps. Reporter Anand Jagatia takes up the story.

Interviewer: Anand Jagatia

Humans are unique among the living primates in having a skeleton that’s well adapted for walking on two feet, right from the bottom of our skulls, all the way down to our toes.

Interviewee: Tracy Kivell

Chimps, gorillas, bonobos, orangutans, even gibbons, are able to walk bipedally, but they do this just sort of infrequently. So, they don’t have adaptations to their skeletons for this kind of behaviour. They can do it when they need to – when they’re carrying a bunch of fruit or something like this.

Interviewer: Anand Jagatia

This is Tracy Kivell, an anthropologist from the University of Kent in the UK. So, if other living apes can only walk on two legs if they have to, how did it become the main form of locomotion for us? Tracy explains that when it comes to theories about how bipedalism evolved in humans, there are two main ideas.

Interviewee: Tracy Kivell

One of those hypotheses has been that we evolved from a knuckle-walking ancestor because chimpanzees, bonobos and gorillas do knuckle-walking most frequently, and there are some features that we share, in our hands in particular as well as our feet, that suggests that our last common ancestor was a knuckle-walker and then things that are leading to humans eventually sort of stood up and started walking on two feet. Then there are other people that have said maybe this knuckle-walking thing seems to be quite specialised and maybe this has evolved sometime after our last common ancestor, and so some people have said actually, it’s this sort of more tree-living last common ancestor that would have spent more time climbing, hanging under branches, doing a bit of walking on two feet on the branches and then, for whatever reason, around 5-7 million years ago would have come down from the trees and started walking on two feet.

Interviewer: Anand Jagatia

So far, fossil evidence for these two theories has been hard to come by. There are ape fossils that date from between 6 and 7 million years ago that show evidence of bipedalism, but these are quite fragmentary and some are considered controversial. This week in Nature, scientists have reported the discovery of an ape species called Danuvius guggenmosi. The fossils, which are well preserved compared to anything found previously, were discovered in Bavaria. They date to 11.6 million years ago, to a time known as the Miocene.

Interviewee: Madelaine Böhme

Actually, we found 38 bones and teeth, and the most important thing is that we can study in the one same individual, several very important joints for the locomotion. So, we have the wrist, we have the hip, we have the knee joint and we have the ankle.

Interviewer: Anand Jagatia

This is Madelaine Böhme, a palaeontologist from Tübingen University and lead author on the paper. The researchers also found two relatively complete limb bones, the ulnar in the lower arm and the tibia in the lower leg. Together, these fossil bones and joints were able to tell the authors a lot about how Danuvius might have walked around.

Interviewee: Tracy Kivell

What the authors have described is that they have the upper arms, at least what’s preserved of it, show features that you see in sort of other Miocene apes and in living apes, in terms of it looks like an arm that was used for being in the trees, for climbing and a bit of suspension. But then when you look at the lower limb, it looks like the posture is actually a much more extended hip joint which is more similar to a human posture. The same thing can be said for the knee. And then at the bottom of that leg bone, there’s also an ankle joint that looks quite stable in terms of the shape of the joint, and that is also something that you see in humans and that we need that stability when you have all of your body mass being sort of carried on two feet instead of four.

Interviewer: Anand Jagatia

While many of these lower limb bones would have been useful for walking on the ground, one showed that Danuvius was definitely still hanging around in trees – the big toe.

Interviewee: Madelaine Böhme

The big toe was really quite big, but contrary to modern humans, the big toe bone, it’s laterally twisted, and a lateral twist in the big toe is an indication that the big toe was opposable like in ancient great apes. It means that the foot was like a hand and it can grasp, for instance, in a tree, so Danuvius was able to stand and to walk on two legs but it did it mostly in the trees.

Interviewer: Anand Jagatia

So, it seems like Danuvius had a skeleton that both adapted it to walking upright in trees with straight extended limbs like a human, but then it also had arms which were suited to hanging from branches. The authors call this form of locomotion extended limb clambering. So, what does this tell us about how humans might have evolved to walk upright? Well, Danuvius wasn’t the common ancestor of modern great apes and humans, but it does provide fossil evidence for a kind of movement half way between walking and climbing that hasn’t been observed before. As Tracy explains, it’s an intriguing possibility that perhaps our ancestors also evolved to walk in a similar kind of way.

Interviewee: Tracy Kivell

What Danuvius sort of brings to the table is it’s providing a more sort of clear picture on how one of these Miocene apes moved around, a new form of locomotion and a new idea of sort of moving around in the trees that so far, I think, is our sort of best model for what maybe our last common ancestor looked like.

Host: Shamini Bundell

That was Anand Jagatia talking to Tracy Kivell from the University of Kent in the UK and Madelaine Böhme from the University of Tübingen in Germany. You can read the paper and an accompanying News and Views article at nature.com.

Host: Benjamin Thompson

At the end of the show this week, we’ll have the News Chat, where we’ll be hearing about an AI that claims that the Sun is at the centre of the solar system – controversial. Coming up now though, it’s time for a quick one-two of science with this week’s Research Highlights, read by Anna Nagle.

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Anna Nagle

Olfactory bulbs relay information about odours from the nose to the brain so without them, having a sense of smell was thought impossible. But that may not be the case. Researchers discovered that some people without olfactory bulbs reported that they were able to smell. By digging through over a thousand MRI scans, the scientists found that the bulbless individuals who could smell were all women, and it was more common among left-handers. This ability was vanishingly rare with just 0.6% of women in the sample able to smell despite the lack of olfactory bulbs. The researchers studied how well two volunteers from this sample could distinguish between different smells and identify scents, and indeed their senses of smell were as good as the average person. It’s unknown how these individuals are able to smell, but the researchers suggest that it shows the brain is even more plastic and adaptable than previously thought. Sniff out that research over in Neuron.

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Anna Nagle

How do you tell the difference between bourbon and Scotch? If reading the label or tasting them seems too straightforward, then you may be able to tell from the residue they leave behind after a drop evaporates. When diluted to 20% alcohol by volume, Scotch whisky leaves a uniform shape after evaporating, whereas bourbon leaves a distinct web-like structure of particles. These whisky webs arise because bourbon is aged in charred oak containers that leave more particles in the liquid than the uncharred containers that Scotch ages in. As the drop evaporates, there are turbulent flows in the fluid which then collapse, leaving the web-like pattern. Different types of bourbon also leave distinct impressions, and so the researchers believe this technique could be used to identify counterfeits. Savour that research over at Physical Review Fluids.

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Host: Benjamin Thompson

This week marks 150 years since the first issue of Nature was published on 4 November 1869.

Host: Shamini Bundell

Yay, happy birthday to us! What were you doing when the first issue came out, Ben?

Host: Benjamin Thompson

How old do you actually think I am, Shamini? Do you know what actually, don’t answer that. It’s really not important. What is important though, is that we’re going all out to celebrate this century-and-a-half birthday. In fact, if you head over to go.nature.com/150, you’ll find a whole host of content: articles, videos, behind the scenes blogs from some of Nature’s staff, including yours truly. There’s absolutely loads there. We’ve also got a series of essays looking at how the last 150 years have shaped science around the world. The final essay in this series come from Phil Ball, a science writer and former editor here at Nature. Phil popped by the studio recently to talk about his essay with Nature’s chief opinion editor, Sara Abdulla.

Interviewer: Sara Abdulla

So, you’ve been doing some looking back for us. I asked you to take a look at the past 150 years of science and have a think about some of the great stuff that’s happened, and whether what has got us to where we are today is going to be able to carry us forward. So, when you had that look back, what were the things that stood out as shining examples of achievements of the past 150 years.

Interviewee: Phil Ball

I do think it’s important that we give science credit for the immense changes in health and medicine and also, when you look 150 years ago, at what we thought even then was our place in the Universe, compared to the view that we have now. I think it makes me proud sort of to be human or to be involved in science that, for example, we can now look at the atmosphere of planets going around other stars. That sort of achievement really needs to be celebrated. One of the papers I was proudest to be the editor of in the early 90s was the one that came out of IBM’s research labs, which used a scanning tunnelling microscope to push around and arrange individual atoms on a surface, and the fact that we had got to that stage from not knowing even at the beginning of the 20th century if atoms were real things at all, these are extraordinary achievements. But I think that quite aside from what science has achieved in discovery, one thing that strikes me is the growing internationalism of science and how there were times during the Cold War and after the World Wars when science kept a channel of communication open, and I think that’s something that we take for granted now. But it’s good to be reminded that at the start of the 20th century, it wasn’t obvious to scientists that that was the right way to view things, that there were plenty of scientists in the European nations, for example, who were quite strong nationalists. And so, I think the fact that that voice of internationalism won out, I think is winning out in science, that’s really something to celebrate as well.

Interviewer: Sara Abdulla

And it’s kind of surprising because one of the things that has come out of the essay series is how much part of nation-building the scientific endeavour has often been. So, the fact that it has transcended that to become something bigger is really thrilling. So, you looked back and you found some things to be excited about, and it also set you thinking about whether the same system is going to take us forward.

Interviewee: Phil Ball

When we look at some of the big challenges that we’re still facing, and I mean climate change is the most obvious, I guess it strikes me that it would be rather extraordinary if this method of doing science and disseminating science that was developed during the 19th century really, from a very selective group of people, basically western men, if that was still appropriate to tackling those big challenges we have now. And I think there are signs, in some of them at least, that perhaps it isn’t going to be adequate and that we need to have a little more expansive thinking and be able to find ways of including within the scientific dialogue a greater diversity of voices but also to listen to a greater diversity of people to understand what are the problems that need to be tackled. I think it’s still possible for science to set itself goals that aren’t necessarily the most urgent ones that these problems create.

Interviewer: Sara Abdulla

So, in your survey of the exciting things to have come from the past 150 years, the strengths of the system that has lowered infant mortality, extended lifespan, discovered extra solar planets and its weaknesses – it’s a system that has left many behind and that doesn’t incorporate the views and the values of so many – what pockets of promising different ways of doing things have you come across?

Interviewee: Phil Ball

Well, I think the first thing I ought to say is, and I’m very conscious that I talked about the people who basically sort of set up the way we do things now, and I’m one of them in a sense. I am a western, white, middle-aged guy, so I think the first thing I want to say is, I’m not necessarily the person to ask about how to do things better and I was reminded of that actually. There was a recent paper in Science from a whole bunch of people that was saying that one thing we need to think about how best to use gene editing is to speak to the local communities of people who are going to be affected in one way or another by those techniques, so that kind of initiative is something that I think we need to see more generally. I think it’s a positive move that science is becoming more open access and I think there are also some signs that some people are starting to think about lab culture. One of the things I would like to see change is the methods of incentivisation in science, where there’s still a sense that what is rewarded is getting there first, getting the discovery first, rather than, for example, has this person been a great mentor, have they developed a healthy research culture within their lab? I think we need to see more of that.

Interviewer: Sara Abdulla

So, here we are at Nature’s 150th birthday, and one thing we do on birthdays is we make wishes. Phil, what would your wish for science be?

Interviewee: Phil Ball

There are some questions that I would love to see answered, and I do actually have a small hope that we will know within my lifetime with fairly good certainty that there is life on another planet because that would really again, change not just what we know about other worlds, it would be a philosophical change. I would love to think that there will be some progress in understanding consciousness. I’m less optimistic about that. But I really would like to see science find a way to address what still seem to me to be the systemic biases and obstacles that exist for women, for minorities, for people with disabilities, and I think what would be great there is to move away from what is often the response of some people to say, well I just look for the best researchers and it doesn’t matter to me what their sexuality is or what their race is or whatever, and to be willing to look at what are the obstacles that clearly exist in those areas to inclusivity and to really address them and again, then, to make science a sort of exemplar for how change can come about in other areas of society.

Host: Benjamin Thompson

That was Phil Ball. You can read his essay along with the rest of Nature’s 150th anniversary content over at go.nature.com/150, and also, keep an eye on your podcast feed because we’ve got a special 150th edition of Backchat coming out later this week.

Host: Shamini Bundell

Now, if that wasn’t enough birthday celebrations already, the journal is also publishing a series of reviews that take a look at the past, present and future of science. One of the reviews being published this week is about vaccines. Reporter Nick Howe went to go chat to the lead author Peter Piot at the London School of Hygiene and Tropical Medicine, and started by asking him just how important vaccines are.

Interviewee: Peter Piot

It’s very hard to imagine a world without vaccines because many of us simply wouldn’t be here. Without vaccination, many people would not make it beyond five years of age because of all the childhood diseases that still exist in some parts of the world or that are coming back, like measles. They would kill millions of people, and so we are talking about something that is also unique in the sense that it’s probably the only biomedical intervention that every single person on Earth needs and most people have had.

Interviewer: Nick Howe

But despite many of these benefits, the many lives that are saved, there are still many major diseases that lack vaccines. Why is that?

Interviewee: Peter Piot

Vaccination seems to be quite a straightforward intervention. Every vaccine, you inject it or you give it as an oral vaccine and that’s it, but it’s an incredibly complex process. First of all, most discoveries never make it to a vaccine because of toxicity. One of the absolute requirements for a vaccine that we inject in a healthy person is that it’s absolutely safe, so it has to pass draconian safety tests. It has to work, it has to protect, and all that can only be found out through a long process of tests in the lab, proof of concept, clinical proof of concept often in animal models but also in people, and then in very large trials. We now have epidemics of measles even in Europe, even in the US, in countries that were considered measles-free, so there is a huge surge in vaccine hesitancy. People are refusing vaccines for a variety of reasons and the consequences are often very immediate. We have epidemics.

Interviewer: Nick Howe

So, we’ll come back to vaccine hesitancy in a minute, but I was just wondering if given all these challenges, just how long can it be before a vaccine is developed. How long can it take?

Interviewee: Peter Piot

It can take well over ten years between the initial discovery and then a vaccine appears on the market or even decades. Take a vaccine against malaria, for example. That’s taken 20 years before it’s now being introduced in a number of countries. We have a vaccine against Ebola, for example, we have two vaccines and they were first tested in 2014 but the original discovery and development happened actually about 10 years earlier. It also means that the investments that have to be made in order to bring a vaccine from discovery to the market are enormous, so that means that very few companies can afford to do that.

Interviewer: Nick Howe

And with these enormous challenges facing this process, is there anything that we can do to streamline it, to make it easier for these vaccines to be brought to the people who need them?

Interviewee: Peter Piot

There are two major issues. One is accelerate the development of vaccines and that requires money and also streamlining of the regulatory approvals and all that so that we can do much better on that. But then the second issue is that there are still close to 20 million children who are not covered by even the basic vaccines and that number has actually not gone down over the last 5-10 years. We’ve made enormous progress and overall in the world, well over 80% of children are protected, so now we need to make an effort in finding and vaccinating those children, those adults, who are marginalised or migrants or poor or in areas that are hard to reach.

Interviewer: Nick Howe

Given that this can take such a long time, and you mentioned Ebola there, how can we respond better in the face of ongoing epidemics?

Interviewee: Peter Piot

The good news is that we now have a mechanism that funds vaccine candidates against epidemic diseases and that’s called CEPI or the Coalition for Epidemic Preparedness Innovations and it’s a coalition of governments, of foundations such as Gates and the Wellcome Trust and of pharmaceutical companies big and small, and it came out of the worst Ebola outbreak that we’ve had in history in West Africa in 2014-2015 and there it was clear that if we wait for market incentives, companies are not going to invest in developing new vaccines.

Interviewer: Nick Howe

So, do you hope that in the event of future outbreaks we’ll be more prepared?

Interviewee: Peter Piot

We will definitely be more prepared. Look at the Ebola outbreak in the Congo. Today we have now two vaccines that are available and that we didn’t have during the big West Africa outbreak.

Interviewer: Nick Howe

So, one thing you mentioned earlier was the problem of vaccine hesitancy and this is where people are refusing or hesitant to take vaccines that we have. What do you think could be done about this?

Interviewee: Peter Piot

I think first of all, we need to understand. Here at our school we have the Vaccine Confidence Index trying to measure and follow what is going on, so to have early detection methods and that’s particularly based on what’s circulating on social media, who can pick that up and then talk to people, go into these communities. But at the end of the day, sometimes if there are major measles epidemics, that puts at risk lots of people and not only other children but can also be elderly people and so on, and at some point, it may be necessary for the government or the state to intervene just as it does for other things.

Host: Shamini Bundell

That was Peter Piot from the London School of Hygiene and Tropical Medicine. To find out more about the unfinished agenda for vaccination, head over to nature.com where you’ll find Peter’s review paper.

Interviewer: Benjamin Thompson

Finally on the show today then listeners, it’s time, of course, for the News Chat and joining me in the studio is Davide Castelvecchi, senior reporter here at Nature. Davide, hi!

Interviewee: Davide Castelvecchi

Great to be here, hi.

Interviewer: Benjamin Thompson

Davide, our first story, well, it’s a huge finding. This changes everything. Results have come out that shows that the planets in the Solar System orbit the Sun. This is enormous.

Interviewee: Davide Castelvecchi

It’s, I would say, a revolution. It’s the Copernican Revolution. At least, it was in the mid-1500s when it was discovered.

Interviewer: Benjamin Thompson

Well, here we are today in 2019, how has this finding been rediscovered and who’s rediscovered it?

Interviewee: Davide Castelvecchi

You shouldn’t ask who, but what. It’s actually a computer and what researchers have done is feed an artificial neural network data about the positions of the planets in the sky and then this neural network came up with the most economical model, the most concise way to represent these motions and figured out well, if you make the planets go around the Sun instead of the Earth, that’s much better.

Interviewer: Benjamin Thompson

Well, what value then, Davide, does this have? I mean we already knew this, so what’s this AI set up to do? Presumably, it’s not just to look at how the planets are orbiting in the Solar System?

Interviewee: Davide Castelvecchi

No, I mean it was a playful way to test a new technique that these researchers invented, a new kind of artificial neural network which they invented for the purpose of discovering new laws of physics.

Interviewer: Benjamin Thompson

Well, that seems like a fairly big thing to try and sort of tackle, and what sort of questions might it be able to answer or at least give insight into?

Interviewee: Davide Castelvecchi

The authors of this papers, what they had in mind was they hoped to find a new formulation of the laws of quantum mechanics because quantum mechanics is notoriously counterintuitive and bizarre and in fact, one of the authors of this latest paper found recently that quantum mechanics contradicts itself. It makes contradicting predictions.

Interviewer: Benjamin Thompson

So, this AI then is hopefully going to cut through that contradiction and get to the real answer – is that the right way to describe it?

Interviewee: Davide Castelvecchi

So, the hope is that a more sophisticated version of this algorithm might someday find a new formulation, a new kind of quantum mechanics that doesn’t have these contradictions in itself.

Interviewer: Benjamin Thompson

So, early days then it sounds like – what are researchers saying about the current work?

Interviewee: Davide Castelvecchi

A lot of people like it, in part because the algorithm produces results that are easy to interpret. Now, this is not often the case. Artificial neural networks are very good at distinguishing objects, for example, but they can’t really tell you how they do it. The way they encode information inside the neural network is spread around millions of nodes which are all interconnected and it’s very difficult to figure out what’s going on. In this particular new technique, they perform a kind of lobotomy on the neural network. They divided it into two sides, one which learns from the data, the other one makes new predictions, and the two sides are connected by very few links, which means that there’s only a very small amount of information that can go from one to the other.

Interviewer: Benjamin Thompson

So, the student half of the AI, if I may, is being fed kind of filtered down information from the teachers’ side, that has access to all of the data.

Interviewee: Davide Castelvecchi

Yes, and the hope is that this kind of technique can help us not only discover new laws of physics but also understand how artificial intelligence gives answers and comes to conclusions.

Interviewer: Benjamin Thompson

Davide, let’s move on to our second story today and let’s maybe take our gaze away from the heavens and, well, go from the very, very large to the very, very small. There’s been a new paper out that’s been discussing the size of a proton, which it turns out has been something that’s been debated by physicists for quite a long time.

Interviewee: Davide Castelvecchi

Yes, there’s been, in fact, a so-called ‘proton radius puzzle’ going on since 2010, and now it seems that we’re finally reaching some kind of conclusion.

Interviewer: Benjamin Thompson

Right, so I think I have to ask and I’m not sure we can even conceptualise it – what sort of size was it thought that a proton was before this new work?

Interviewee: Davide Castelvecchi

We’re talking about something very, very small, much smaller even than an atom. A proton is about a femtometre wide. That’s a millionth of a millionth of a millimetre.

Interviewer: Benjamin Thompson

And how on Earth do you go about actually measuring that, and presumably you haven’t got a ruler that’s that small.

Interviewee: Davide Castelvecchi

There’s been two main ways people use. One is to look at the energy levels of electrons in an atom, because these are affected by the size of the proton, you can measure those energy levels and kind of deduce or estimate the size of the proton itself, which is in the nucleus. The other one is kind of reminiscent of the way Ernest Rutherford discovered the atomic nuclei in the first place in 1909. In the more recent versions of this experiment, physicists have estimated the size of protons by firing beams of high-energy electrons at molecules of hydrogen.

Interviewer: Benjamin Thompson

You described it as the proton radius puzzle, Davide. What is this puzzle and why is it so hard to solve when you say people have been working on it for a while?

Interviewee: Davide Castelvecchi

Yes, so for a long time, both types of techniques had kind of converged on a very highly precise value which was a radius of about 0.8768 femtometres. And then in 2010, a kind of new twist on an experiment found that the proton was actually smaller. It was 4% smaller than the accepted value.

Interviewer: Benjamin Thompson

And what’s happened now then, Davide?

Interviewee: Davide Castelvecchi

Then there’s been a number of experiments that have kind of confirmed this smaller size of the proton and they were all of the first kind of experiments that looked at the energy levels of electrons in an atom. And now, for the first time, we have a scattering experiment, one of these particle beam experiments, also found a smaller radius consistent with the 2010 measurements but not with the earlier accepted values.

Interviewer: Benjamin Thompson

Well, is this the end of the story then, Davide? Has the proton been defined now in terms of its radius?

Interviewee: Davide Castelvecchi

A lot of experts seem to think so. The question though is why did those old experiments find a larger radius because until we’ve understood that, there will be still this open question – why is it that if you measure in one way you get a number and if you measure in another way you get a different number?

Interviewer: Benjamin Thompson

So, the puzzle might not be quite finished just yet, but sort of zooming out a little bit Davide, what does this result mean for physics? Can this be used in anyway at all?

Interviewee: Davide Castelvecchi

These are called fundamental constants for a reason and they’re published in handbooks. A lot of experimentalists take these numbers as the starting point for their experiments, so it is quite important to get the numbers right.

Interviewer: Benjamin Thompson

Well, Davide, thank you so much for joining us today. Listeners, for more on those stories head over to nature.com/news.

Host: Shamini Bundell

That’s all for this week, but don’t forget it is Nature’s birthday week where we’re celebrating being nearly as old as Ben, so head over to go.nature.com/150 where you can find all that extra content. I’m Shamini Bundell.

Host: Benjamin Thompson

And I’m Benjamin Thompson. Thanks for listening.