NATURE PODCAST

Podcast: Bumblebees, opioids, and ocean weather

Benjamin Thompson and Adam Levy bring the latest science news to your ears.

This week, more worries for bees, modelling the opioid crisis, and rough weather for seas.

In this episode:

00:45 Bad news for bumblebees

A study finds potential problems with a pesticide that may replace neonicotinoids. Research paper: Siviter et al.; News & Views: An alternative to controversial pesticides still harms bumblebees

06:28 Stormy seas

Understanding how to protect our oceans means understanding the weather within them. Research paper: Frölicher et al.; Comment: Biologists ignore ocean weather at their peril

13:01 Research Highlights

A fish that grows up fast; and a glimpse inside a volcano. Research Highlight: A record-setting fish grows up at breakneck speed; Research Highlight: Volcano’s molten heart revealed in detail

14:42 Charting crisis

The researchers attempting to use modelling to tackle America’s opioid crisis. Feature: How digital drug users could help to halt the US opioid epidemic

23:05 News Chat

RNA interference makes its medical debut; and CRISPR catalogues a mouse embryo’s development. News: Gene-silencing technology gets first drug approval after 20-year wait; News: CRISPR ‘barcodes’ map mammalian development in exquisite detail

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Transcript

This week, more worries for bees, modelling the opioid crisis, and rough weather for seas.

Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, a new concern for bumblebees, the researchers mapping opioid use in the US…

Host: Adam Levy

And the importance of understanding the weather in our oceans. I’m Adam Levy.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

[Jingle]

Interviewer: Benjamin Thompson

Last weekend, I went to a barbecue in my friend’s garden and of course, being the UK, it was a bit drizzly, but we barbecued anyway. We were kept company by a couple of bumblebees that were loving the lavender plants and spent a good chunk of time bumbling around the purple flowers looking for nectar. But bumblebees’ clumsy quest around flowers actually makes this type of bee super important, as Harry Siviter from Royal Holloway, University of London explains.

Interviewee: Harry Siviter

Bumblebees are absolutely vital for pollination services, you know, for agricultural crops and for wildflower pollination as well. We know that bumblebees are absolutely fantastic pollinators, and this is basically because they’re so big and such clumsy pollinators. They’re much more effective pollinators than other species of bee and they’re really, really important for things like tomatoes, strawberry pollination, raspberry pollination, and they’re very, very important to our economy, and obviously for conservation as well.

Interviewer: Benjamin Thompson

But in spite of their importance for the world around us, bumblebees are having a pretty rough time of it, with numbers of certain species in decline.

Interviewee: Harry Siviter

The environment that a bumblebee finds itself in now is very different to one it would have found 50-100 years ago. Intensification of agriculture means that there’s less food around, there’s been an increase in diseases and parasites due to moving of bumblebees around the world, and of course there’s the emergence of insecticides – some of them have now been shown to have negative impacts on important pollinators such as bumblebees.

Interviewer: Benjamin Thompson

Many bumblebee species are social, living in nests with a lifecycle that revolves around a queen. To protect this lifecycle and those of other bees, the European Union voted to ban the outdoor use of three insecticides earlier this year. These all belong to a particular class called the neonicotinoids, which are still in use in many parts of the world. In a Nature paper this week, Harry and his colleagues have been looking at the potential effects on bumblebees of a new group of insecticides, called the sulfoximines. These have been suggested as an alternative to the neonicotinoids and have been licensed for use in several countries. The team looked at one particular sulfoximine insecticide called sulfoxaflor Products containing sulfoxaflor have been approved for use in several European countries and more approvals are on the cards. The team were interested in the effect that low concentrations of sulfoxaflor had on the bumblebee species Bombus terrestris. To find that out, they first had to set up some colonies in the lab.

Interviewee: Harry Siviter

So, what we did was, we collected queen bumblebees from Windsor Great Park, we took them back to the lab and we encouraged them to rear colonies. Once the colonies were going strong, we exposed half of them to a sucrose solution which had a very, very small concentration of sulfoxaflor in it.

Interviewer: Benjamin Thompson

After two weeks of feeding the bumblebees, the colonies were taken outside to the campus ground, and left to forage on their own. Harry kept an eye on them.

Interviewee: Harry Siviter

I would go out at night time in a bee suit. I would open the lid to these colonies and have a look at them and see how they were getting on. I would record worker number, reproductive output, so the number of males and queens that they were producing, and also look at the food stores in the nest.

Interviewer: Benjamin Thompson

Early on in the colony’s lifecycle, Harry found that sulfoxaflor-exposed colonies produced fewer worker bumblebees than the controls, and other differences became apparent as the colonies developed.

Interviewee: Harry Siviter

Colonies that had been exposed to sulfoxaflor at the start of their lifecycle, were producing fewer males and fewer queens. So, if a colony doesn’t produce males and queens it has no reproductive output, has no fitness, has no bees going in to the next generation. So, we found under our regime of sulfoxaflor exposure reduced the reproductive output of bumblebee colonies.

Interviewer: Benjamin Thompson

The team showed a 54% reduction in the reproductive output of the sulfoxaflor-treated colonies, meaning that fewer reproductive offspring were present. The production of males and queens is something that happens late in a bumblebee colony’s lifecycle, and Harry hypothesises that the effects on the workers early on might be having a knock-on effect later. Of course, this is a first study that looks into the effect that this insecticide has on bumblebees and it uses particular conditions. That said, Nigel Raine from the University of Guelph, who is the author of a News and Views article that accompanies this research, thinks that the way the study was set up, with both a laboratory and an outdoor section, means it can offer some useful insights.

Interviewee: Nigel Raine

Another really nice feature of this experiment is that the authors have chosen to use colonies that have been raised from wild-caught queens in the local environments, and obviously, they’re addressing a question with a class of insecticide for which we have very little toxicological information, certainly at this kind of level.

Interviewer: Benjamin Thompson

Nigel suggested that important next steps need to be taken. These include working out the mechanisms of the effects on bumblebees, whether the results are mirrored in agricultural environments, and what the effects are on different bee species. He says that given all the work to understand the effects of neonicotinoids, there is a need to unpick the potential impacts of any insecticides that might replace them.

Interviewee: Nigel Raine

We need to be sure when we’re talking about the relative risks of pesticides, that we are also doing our due diligence to look at similar sorts of sub-lethal effects from other classes of pesticide, be they existing classes of pesticide or emerging classes like these sulfoximines, which may be likely to be used much more widely in agriculture as a result of other policy restrictions. So, simply replacing one class of pesticide with another class of pesticide without fully understanding the risk to the pollinators would be a misstep, in my opinion.

Interviewer: Benjamin Thompson

That was Nigel Raine from the University of Guelph in Canada. Before him, you heard from Harry Siviter from Royal Holloway, University of London here in the UK. You can read Harry’s paper, and Nigel’s News and Views, over at nature.com/nature.

Interviewer: Adam Levy

What do you think about when you think about the impacts of climate change on the oceans? Maybe you think about sea level rise, perhaps ocean acidification, or the rising temperatures of the seas. But we typically think of each of these issues in broad brushstrokes. Take sea level rise – we might talk about a metre of sea level rise by the end of the century, but we rarely describe how such a change varies from place to place, from month to month. This week’s Nature is publishing a Comment piece and a research paper, both of which emphasise the variability of the ocean’s physical characteristics – in other words, the ocean’s weather. First, the paper. The study describes something that we’re used to considering on land – heatwaves. I called up oceanographer Thomas Frölicher, who led the study, to find out what a marine heatwave is.

Interviewee: Thomas Frölicher

So, a marine heatwave is actually a period of extreme warm sea surface temperature that persists for days to months and can extend up to several thousands of kilometres in the ocean.

Interviewer: Adam Levy

And that’s something that we have already started thinking about on land, you know. I feel like it’s really common for us to talk about heatwaves on land.

Interviewee: Thomas Frölicher

And we also know quite well that extreme climate and weather events overland shape the structure of terrestrial biological systems but in contrast, we know very little how extreme events in the ocean will change under global warming.

Interviewer: Adam Levy

But why is it important that we think about heatwaves instead of just thinking about kind of this global average temperature increase and things like that?

Interviewee: Thomas Frölicher

Heatwaves can actually disturb entire marine ecosystems for a long time, so it’s not only impacting marine organisms and ecosystems, but also the weather systems in the atmosphere, but also human systems on land. For example, the Peruvian marine heatwave in early 2017 caused heavy rainfall and flooding on the west coast of tropical Southern America and the Andes mountains. And then the heavy rain triggered numerous landslides and flooding which resulted in a death toll of several hundred.

Interviewer: Adam Levy

Now, we know that these heatwaves happen, as you’ve just said, but what in this study were you looking to investigate regarding ocean heatwaves?

Interviewee: Thomas Frölicher

Yeah, so we used the daily global sea surface temperature data from satellite observations which cover the period 1982-2016. And we actually detected a doubling in the number of marine heatwave days and we showed that these changes are mostly outside the range of those expected from natural internal variability. So, this indicates that the climate change signal is already strong enough to be detected in observations.

Interviewer: Adam Levy

So, that’s what you do looking back. What about the future though?

Interviewee: Thomas Frölicher

What we fear is that if global atmospheric surface temperatures were to rise by 3.5 degrees Celsius relative to preindustrial levels by the end of the 21st century, the number of marine heatwave days will be 41 times higher than in preindustrial times. This is a huge increase, and for me it’s somehow worrisome given that the 3.5 degrees global warming is predicted to result from current national policies for the reduction of global carbon emissions. The increase is much larger for marine heatwaves than for land-based heatwaves.

Interviewer: Adam Levy

Thomas Frölicher there. Nature’s also publishing a Comment piece on the topic of ocean weather, and in particular the need for ecologists to take into account just how variable the seas can be. Amanda Bates, one of the authors of the Comment piece, emphasises just how much the ocean can change. Even studies like Thomas’, looking at extreme events, don’t capture the level of detail that ecologists might need.

Interviewee: Amanda Bates

In the ocean, we also have a lot of fine-scale variability. We can have upwelling where we get cold water coming up to the surface and that can change temperature by tens of degrees within hours. We plot these out in these large, kind of greater scales, but it completely misses all of this fine-scale variability in the ocean. And that by trying to understand the variability, what will emerge from that are hopefully some tools or areas or regions that we can prioritise and then come up with some kind of conservation or management tools.

Interviewer: Adam Levy

Amanda is hoping, for example, for an understanding of refuge sites in the ocean, where vulnerable species can potentially flourish, even as the oceans as a whole continue to warm. But getting data on the fine-scale variability of something as massive as the ocean is no easy task. Observations from satellites, like the ones Thomas used in his study, have a limited resolution, and can’t see deeper into the ocean. But Amanda stresses that more and more sensors are being deployed in the seas.

Interviewee: Amanda Bates

So right now, we are starting to build up this local-scale, fine-scale information. We’re right on the cusp of this kind of big data era, where we’re going to have information on our globe in high-resolution, and as biologists we can start to take advantage of this amazing technology that’s coming out of the physical world.

Interviewer: Adam Levy

For Thomas, this is a key point. In order to understand and protect our changing seas, researchers from different disciplines need to work together to understand the oceans in all their detail.

Interviewee: Thomas Frölicher

I think there should be more collaboration among physical oceanographers and those who are marine biologists to really tackle this problem together and to collaborate across disciplines to make nature progress.

Interviewer: Adam Levy

That was Thomas Frölicher of the University of Bern in Switzerland. You also heard from Amanda Bates who’s at the Memorial University of Newfoundland in Canada. Find Thomas’ paper and Amanda’s Comment over at nature.com/nature.

Host: Benjamin Thompson

Coming up later in the show, we’ll be hearing about the researchers using CRISPR to track the development of a mouse embryo in incredible detail. That’s coming up in the News Chat. Before then, Noah Baker is here with this week’s Research Highlights.

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Interviewer: Noah Baker

Stop the press! The new winner of the coveted ‘fastest-maturing vertebrate’ title has been announced. It’s the turquoise killifish. Hailing from Mozambique, this tiny critter takes just two weeks to develop from egg to sexual maturity. Killifish spend much of their life as embryos buried in the soil, waiting out the long dry season until the rains come and form small pools. Then the race is on to hatch, mature and lay more eggs in the soil before the puddles dry up - often that takes less than 3 weeks. Researchers found that wild killifish in Mozambique develop even faster than their captive counterparts. More on that study in Current Biology.

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Interviewer: Noah Baker

Volcanologists have been plumbing the depths of Mount St Helens to form the best picture yet of the infamous volcano’s internal, well, plumbing. Researchers set off a series of controlled explosions around the mountain and traced the shockwaves as they moved through the ground. These seismic waves slowed as they passed through a patch between 3.5 kilometres and 14 kilometres below the surface. Now, seismic waves move more slowly through hot material, so that suggests that this is the volcano’s magma chamber. The slowest movement was between 4 and 6 kilometres down, suggesting that that’s where the most molten material is amassed. That research is hot off the press in the journal Geology.

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Host: Adam Levy

Each day, Americans consume more opioids than people in any other country. And each day, over a hundred Americans die from opioid overdose. The increase in deaths from opioids, which includes both illegal drugs like heroin and prescription painkillers, is so large that the American Center for Disease Control and Prevention have described it as an epidemic. Shamini Bundell has been finding out about the complex factors involved.

Interviewer: Shamini Bundell

Statistics show that in the US, over the past few decades, prescriptions for opioids have increased, as have the number of deaths caused by opioids. It might seem like a simple link, but understanding and stopping this ongoing crisis in the US is anything but simple. The links between prescription drug use, illegal drug use, the development of addiction and the resulting health problems are a complex mix of social, cultural and medical factors. Here’s Georgiy Bobashev.

Interviewee: Georgiy Bobashev

For many years, I’ve been studying various aspects of drug use and addiction and I got really fascinated by how complex it is.

Interviewer: Shamini Bundell

Georgiy isn’t a neuroscientist or a clinician. In fact, he started his career by studying physics, before moving on to biological modelling. But he has a personal interest in questions around drug use.

Interviewee: Georgiy Bobashev

I’ve seen a number of very good friends of mine who fell victim to drug use, alcohol dependence, and I was curious, why, when we all grow together, we go together to the same school, we grow in the same society, and why some people get addicted and others go ahead with their careers?

Interviewer: Shamini Bundell

For Georgiy, the solution to unpicking these kinds of questions lies in creating mathematical models.

Interviewee: Georgiy Bobashev

We’re trying to turn everything that we observe around us into mathematical terms. And actually, I think we all, or majority of us, think in models. For example, if you’re planning a party, as you’re thinking through what will happen at your party, you’re thinking okay if we’re having 20 guests I need to make sure I have enough silverware, have enough plates and food – that is actually modelling. You actually make these models about what is most likely to happen.

Interviewer: Shamini Bundell

But Georgiy’s models are a bit more complex than planning a party. They need to account for the kinds of drugs available to people, the neuroscience of addiction, the behaviour of drug dealers, the monitoring of prescription drug use, the community support available for users and the impact of government policies.

Interviewee: Georgiy Bobashev

Drug use and addiction is an extremely complex system. There is not a single factor, not one factor that you change it, and that solves the problem.

Interviewer: Shamini Bundell

This means that Georgiy’s models also need to be extremely complex. His approach is something called agent-based modelling. It works by creating a virtual world full of individual agents, representing in this case people. In one case, they’ve created a virtual town, filled with 10,000 people including doctors who can prescribe pain-relief medicine, drug dealers who can supply illegal opioids, and users, some of whom who have chronic pain conditions.

Interviewee: Georgiy Bobashev

Think of a computer game. Think of a virtual society where we try to model individuals and a community of individuals, and different individuals will have different rules of behaviour. These rules, they’re based on observations, they’re based on epidemiological studies.

Interviewer: Shamini Bundell

Once the model is set up, researchers can adjust specific parameters and see the effect so they can test ideas about what might work to decrease the number of heroin users or new addictions to prescription drugs or overdose deaths. These kinds of agent-based simulations are more complex and hopefully more accurate than previous models. But in order to be as accurate as possible, these models, of course, need accurate data. Big data about prescriptions, hospital admissions and so on, are becoming more easily accessible, but there are other data which are less easy to obtain. Enter Daniel Ciccarone, a clinician and public health specialist. Rather than looking at the big numbers, Daniel and his team have been investigating the behaviour of individual drug users.

Interviewee: Daniel Ciccarone

We observe heroin use and users in their natural environments. Because each chemical version of heroin is used differently, we’re very interested in the behaviours of the users themselves.

Interviewer: Shamini Bundell

The culture and practices of drug users has a big impact on their health and details from Daniel’s observations can help feed Georgiy’s models. The observations can also suggest explanations for unexpected patterns seen in the statistics. One example of this has to do, not with the health impacts of opioids themselves, but with the prevalence of HIV among drug users. It’s a problem that Georgiy and Daniel have been working on for some time. HIV can be spread by sharing needles – which explains why it is common in heroin users – but it couldn’t explain a significant difference in HIV rates between the East and West Coasts of the United States.

Interviewee: Daniel Ciccarone

The HIV rates among injection drug users were so different based on East Coast versus West Coast. And there were wide published speculations about why West Coast does have much lower HIV prevalence rates.

Interviewer: Shamini Bundell

One notable difference between the two areas was the kind of heroin used. On the East Coast, refined powder heroin from South Asia and South America was common. On the West Coast, less refined ‘black tar heroin’, a dark gummy substance from Mexico, was widely available.

Interviewee: Daniel Ciccarone

We made some systematic observations on the East Coast, on the West Coast, and what we discovered is that black tar heroin quite likely is protective for HIV.

Interviewer: Shamini Bundell

The use of black tar heroin might actually help protect users from HIV transfer. To find out why, Daniel and his team observed the ways in which people actually use the drug.

Interviewee: Daniel Ciccarone

It’s protective for HIV because it’s a fussy drug. It requires heating to go into solution – powdered heroin does not. Black tar heroin, because it’s sticky, it freezes up injection equipment, you have to rinse it out vigorously. Well that rinsing is going to reduce the HIV viral load in the syringe.

Interviewer: Shamini Bundell

This example shows how observations on the ground can explain wider patterns. These explanations can then be tested in Georgiy’s models. In this case, modelling the behaviour of drug users could help predict future problems in the US as a whole as the drugs trade changes.

Interviewee: Daniel Ciccarone

The country is moving towards powdered heroin. The Mexican criminal trafficking organisations have suddenly learnt how to create a powdered heroin which is beginning to replace the solid black tar heroin. If this continues then it places a larger percentage of the heroin-using population in the United States at risk for HIV.

Interviewer: Shamini Bundell

If that happens it could have immediate policy implications. Systems could be put in place now to prevent or mitigate a future HIV epidemic. Changes like a switch from black tar to powdered heroin can happen rapidly so these ongoing observations and data collecting and modelling need to be able to keep up. Here’s Georgiy again.

Interviewee: Georgiy Bobashev

The traditional research takes years to get a deep understanding of underlying phenomena and to develop reliable models. Here we see that the epidemic is changing very rapidly and we need to respond to it as quickly as possible, because people are dying every day.

Interviewer: Adam Levy

That was Georgiy Bobashev from US-based research organisation RTI International, and Daniel Ciccarone from the University of California, San Francisco. Both also appear in a Feature in this week’s Nature that further explores the role of modelling in the US opioid crisis. Find that at nature.com/news.

Interviewer: Benjamin Thompson

Finally then listeners, it’s time for the News Chat and I’m joined here in the studio by Heidi Ledford, senior reporter here at Nature. Hi Heidi.

Interviewee: Heidi Ledford

Hi.

Interviewer: Benjamin Thompson

Right then Heidi, our first piece today is a story that’s been two decades in the making. What’s been going on?

Interviewee: Heidi Ledford

Oh, it’s the first drug based on RNA interference. So, RNA interference is a technique that you can use to silence specific genes, and back when it was first discovered and first characterised there was a lot of hope that this could be a really groovy way to make new medicines, that you could use it as a way to shut down, for example, maybe the production of mutated in proteins in someone who has a genetic disorder. All kinds of possibilities.

Interviewer: Benjamin Thompson

Well as I said at the start there, so two decades in the making. I mean, RNA interference, or RNAi as it’s known to a lot of people, I mean I remember reading that at the backend of the 90s when I was doing my undergraduate.

Interviewee: Heidi Ledford

It was so exciting, wasn’t it? I mean when that stuff first started coming out, it was, I mean beyond the medical applications it was just this whole new world in biology. It was, you know, RNA was doing so many more things than we realised, you know, as people started to discover this it was like this whole world that had been existing there that we just didn’t know. But, as is often the case when you have a new technology and you’re trying to somehow harness that to make a new medicine, you run into all sorts of problems along the way that have to be solved first.

Interviewer: Benjamin Thompson

Well maybe we can talk about some of those problems when we actually talk about this new drug, which, Patisiran, I believe it’s called.

Interviewee: Heidi Ledford

That’s right.

Interviewer: Benjamin Thompson

What does it do?

Interviewee: Heidi Ledford

So, Patisiran helps to shut down production of a protein called transthyretin, and this is something that’s very useful for people who have a rare genetic disorder called hereditary transthyretin amyloidosis. So, in that condition the mutated transthyretin protein starts to accumulate in different organs of the body and then can interfere with their normal function.

Interviewer: Benjamin Thompson

And Patisiran’s job then is to stop this happening?

Interviewee: Heidi Ledford

So, this protein is produced primarily in the liver. Patisiran can then come in and shut down expression of the gene that produces then the protein.

Interviewer: Benjamin Thompson

And being sort of liver-related seems super key for this sort of first RNAi drug.

Interviewee: Heidi Ledford

Yeah, that’s right. So, one of the stumbling blocks that the field faced was the difficulty of trying to get their RNA molecules into the cells where they needed to shut down a particular gene’s expression. Anyone who’s worked with it in the lab knows that RNA can be a bit fickle. It degrades quite easily, there are lots of enzymes out there that love to chew it up, and those enzymes are plentiful in the bloodstream. You also then have to get the RNA, you know, out of the bloodstream, into the tissue where it’s needed, into the cells where it’s needed, and so forth. So that was a really big stumbling block. The liver happens to be a place where it’s easier to get these RNA molecules into, and so that became then one of the primary targets for companies that were developing therapies based on RNAi.

Interviewer: Benjamin Thompson

Well, this is the first one to be approved by the regulators. I mean what happens next, Heidi?

Interviewee: Heidi Ledford

Well there are lots of other RNAi therapies waiting in the wings. Some of them are coming along in clinical trials already, and then there’s some preclinical work that’s moving along the pipeline. People are looking at trying to use RNAi in the central nervous system and all sorts of different places. I think what the field sort of recognised, you know, that there wasn’t necessarily going to be a one-size-fits-all solution to the delivery problem, that they have to kind of tackle different organs and different tissues one by one.

Interviewer: Benjamin Thompson

So, although it may have taken sort of 20 years, it looks like finally then we’re knocking on the door.

Interviewee: Heidi Ledford

That’s right, and it’s had some other effects as well because now, you know, there’s a lot of excitement again about a new technology that might lead to amazing new therapies, and that technology is CRISPR-based gene editing. But they also, that field is also likely to face some difficulties in terms of getting all the molecular components that it needs into the cells where they’re needed. So, that field is borrowing heavily from what was learned by the researchers who worked with RNAi before them.

Interviewer: Benjamin Thompson

Well Heidi, that’s a beautiful segue. I mean you and I always seem to end up talking about CRISPR – I don’t know whether it’s on the News Chat or on Backchat, but that’s what our next story is about again. What’s going on in CRISPR land?

Interviewee: Heidi Ledford

We’ve got another news story about a new way to use CRISPR to track the development of a mammal, a mouse, from a single egg into an embryo that has millions of cells.

Interviewer: Benjamin Thompson

Oh my goodness, that seems like a heck of a job!

Interviewee: Heidi Ledford

It is a lot of cells, and it’s the first time that they’ve managed to do this kind of work in an organism as complicated as a mouse.

Interviewer: Benjamin Thompson

Well, I mean, obvious question number one – why would you want to sort of track all the cells in a developing sort of embryo or fetus?

Interviewee: Heidi Ledford

Well I think it tells you, well for one thing it sort of gets to the heart of developmental biology, right? How do you even form these complicated bodies and tissues and organs? I think it’s one of the basic questions and it really gets to the heart of that, but it can also tell you what goes wrong, you know, sometimes when something goes wrong during development and how that might be fixed.

Interviewer: Benjamin Thompson

Well, how does CRISPR kind of fit into this endeavour?

Interviewee: Heidi Ledford

Well CRISPR is really powerful because it allows biologists to track the lineage of an individual cell as it divides and then divides again. What CRISPR does is allow them to essentially create a barcode, in a way to sort of individually tag each cell so you have this barcode in the cell. These researchers, you know, edited 60 different sites in the genome, for example, to create this barcode. And then the cell divides, and then CRISPR works again and it sort of modifies that barcode in a unique way potentially in each cell. And then those cells divide again, the barcode gets modified again, and so you can sort of track back when you sequence these cells and the genome, you can track back the changes that were made and figure out which cell was descended from which other cell and so forth.

Interviewer: Benjamin Thompson

Wow, so a sort of hereditary tree then?

Interviewee: Heidi Ledford

Exactly. You get a family tree of your cells, yeah.

Interviewer: Benjamin Thompson

Well Heidi, this study has sort of just been published, but have any results come out of this work so far?

Interviewee: Heidi Ledford

Well they were already, I mean they only went up to 12-day-old mouse embryos in this study, but they were already able to glean some information about brain development, for example, and which parts of the brain developed first, followed by, you know, other parts of the brain, tackling issues that developmental biologists had been wondering about for quite some time.

Interviewer: Benjamin Thompson

Well, finally then Heidi, I mean where does this technique go next then?

Interviewee: Heidi Ledford

Well, you know, I think ultimately they would hope to be able to use this technique to trace back the cell lineage of every cell in an adult mouse, for example. And then along the way they can adapt the technique to use to study things like the development of cancer and other disorders.

Interviewer: Benjamin Thompson

Well Heidi, thanks for joining us. I’m sure we’ll have you back on next time there’s a CRISPR story. Listeners, you can find out all about the latest science news over at nature.com/news.

Host: Adam Levy

And that’s it for another week in science. As ever, make sure to give us a follow over on Twitter @NaturePodcast for all the latest updates. Until next time, I’m Adam Levy.

Host: Benjamin Thompson

And I’m Benjamin Thompson. Thanks for listening.

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