S525: 2022 Unzipped
Hello, and welcome to Genetics Unzipped - the Genetics Society podcast, with me, Dr Sally Le Page. It’s the final episode of 2022, so we’re looking back at our favourite genetic stories of the year plus some bonus bits from our interviews that have never been heard before.
Don’t ask me how, but somehow we have reached the end of 2022, and it’s been yet another year with an unprecedented number of unprecedented events. Covid-19 continued to circulate around the world, Russia invaded Ukraine and the Queen died.
But in the world of genetics, there’s been plenty of good news stories this year too. Back in January, surgeons performed the first ever operation to transplant a heart from a genetically modified pig into a human, which we covered in episode 8, Have a Heart. The 2022 Nobel Prize in Physiology or Medicine went to Swedish geneticist Svante Pääbo for his work on the genomes of extinct human species - which we covered in episode 21, Past to Present. And of course 2022 marked the bicentennial of the birth of Gregor Mendel - which, you guessed it, we covered in episode 16, Hap-pea 200th Birthday Mendel.
One of my favourite parts of producing the Genetics Unzipped podcast is getting to chat to so many amazing researchers and geeking out with them about their niche areas of interest. And one of my least favourite parts is having to leave some fantastic answers on the cutting room floor as there simply isn’t enough time in each episode to include everything.
Well as a Christmas treat, we’ve prepared a selection box of some of the best bits from our guests that never made it into the final episodes.
S5.10: Squid Game: the strange science of cephalopods
And to kick us off, I’m taking you back to May and episode 10, which was Squid game: the strange science of cephalopods. I’ll let you in on a little secret; Kat and I had both watched Squid Game, thought it would make a good title for an episode and just kinda hoped that we would find some interesting stories about genetics and cephalopods. Thankfully, squid scientists are doing some fascinating research, so not only did I get to find out about sending baby squid into space from Jamie Foster, I also got to chat to the unapologetically enthusiastic squid superfan, Sarah McAnulty. Here’s a little snippet of our chat that sadly got cut for time:
Sally: Putting 3D glasses on a cuttlefish. What's that all about?
Sarah: So that's all about understanding how these animals perceive their environments because a huge amount of research that goes into cephalopods is understanding how they use this dynamic colour-changing skin to really, really effectively camouflage in a lot of different situations.
Sally: Really effectively. I finally got to see an octopus when I was diving in the Red Sea. It's not the colour, everyone tells you about the colour change, it's the texture change.
Sarah: I know! Yes.
Sally: It just looked like coral. It was bizarre.
Sarah: So those texture things, I call them extreme goosebumps. They're called papillae and they allow the animal to just do colour, texture, the whole thing. They're really good at it.
Sally: But this group of animals is famously so colourful and obviously camouflage is to do with colour. I've read that they can't even see colour!
Sarah: They can't even see colour. I know. It's unbelievable. So here's the thing, I think we forget how much more colour we see on land than is available in the ocean.
Sarah: We can see these bright reds, yellows, oranges, blues, greens and browns and everything really effectively because the air that we hang out in doesn't absorb a lot of that. But in the ocean, everything just kind of looks blue after a while. So, unless you're in incredibly shallow water, it's less relevant.
Sarah: Not irrelevant, but less relevant to be able to see your reds and yellows and oranges as everything else. Once you get 30 or 50 meters down, good luck seeing colour. So it's not as relevant to them as it would be to us, or it would be to a bird.
Sally: But then why do they bother having such colour-based adaptations like camouflage? And don't they do visual signalling with each other based on the colour of their skin?
Sarah: They do, yes. A lot of them communicate via the patterns on their back. We also think that they're using the polarisation of light in addition to the wavelength or colour of light in order to communicate with each other.
Sarah: We can't see polarised light. Everything just looks the same direction to us. But they have the ability to see the polarisation of the light. They can see that and they can't really see the wavelengths as well. So a lot of the effectiveness of their camouflage really comes down to lights and darks.
Sarah: They're breaking up their body pattern using big chunks of dark and white patterns. That's one of the things that they do. I don't really know how they're so effective at matching when they can't see colour, but they seem to manage it. That's one of the big, "we don't knows" that's still left in squid biology.
Sally: And it's a big "we don't know". I was shown this picture of cuttlefish wearing old-school 3D glasses, the blue/red ones. But nowadays, modern 3D films are all done with polarised lights. So you're telling me that not even now in 2022, can squids watch a decent 3D film?
Sarah: I suppose!
Sally: They'd just get super confused because they'd be processing both polarised things in a different way.
Sarah: The question of how the different visual systems in animals translate to their perception and what they see in their mind is such a cool black box kind of question. Knowing that a mantis shrimp has what, 12 cones - colour receptors. If we had their hardware with our processing power, what would we be able to see?
Sarah: I think it would be totally amazing. But they have different processing power in their brains. We think that they really can't see a lot more colour than we can just because they've got all of the ability to take the information in of what colour is there, but not the ability to multiplex it all together in their brains and get that perception.
Sally: What a waste!
Sarah: What a waste. I know.
Sally: Because if you think of the difference in humans. The difference between having two cones and three is the difference between red-green colour blindness and full vision. So add another nine onto that...
Sarah: The world would be a wild place to live in for sure.
Sally: Maybe even our brains couldn't cope with it. Maybe that's why mantis shrimps have adapted to not have their brains blown up by so much colour.
That was Sarah McAnulty and you can listen to the rest of the conversation in episode 10.
S5.14: Genes, brains and the mind: how much of your personality is encoded in your DNA?
Next up, we’re travelling back to July and episode 14, which was Genes, brains and the mind: How much of your personality is encoded in your DNA. Of all the episodes I produced, no other has thrown me into quite such an existential crisis as this one as geneticist, neuroscientist and author, Kevin Mitchell and I grappled with questions like: Where do our personalities come from? Can we change who we are or are our personalities fixed from birth? And, does free will even exist? You know, the small stuff. But to understand all this, we first had to grapple with another big concept; heritability…
Sally: We're talking about inheriting things. A big question for you: what is Inheritability?
Kevin: That's a tricky one.
Sally: Because it's not something I've thought about a lot and it really takes a while to get your head around it.
Kevin: It does and it's unfortunate it's a super technical, statistical term, but it doesn't sound like it should be.
Sally: No, if something's heritable, it means that I'm gonna get it from my parents.
Kevin: So it sounds like the word heredity, right? Heritability. And it's not, it has a very technical term. It doesn't apply to individuals at all. It gets back to this example I was talking about earlier, of looking at your herd of cattle and saying, "when I breed them together, how much of a difference do I get in my trait from one generation to the next?"
Kevin: If you're looking at milk yield, you can breed for it. So if you select the ones with the highest milk yield, then the next generation will have even higher. Whereas if you have jersey cattle with black and white patches on them and you select for black and white patches where they are, that's actually not heritable. That's an expression of randomness. Of course, you can have other things that are just due to environmental differences.
Kevin: What heritability is, statistically speaking, is the percentage of variants in some trait that you observe in a population that is attributable to genetic differences within that population
Sally: Do those genetic differences have to be in the genes? Because this is the thing, we have all of this random side of things, but then also we have the environmental side of things. When we start talking about human behaviour, one of the things that you argue is that the environment we seek out is itself partly genetic, like we are drawn towards certain environments. So does that count as genetic or does that count as environmental?
Kevin: It's really, really tricky. The point of things like twin studies and family studies, and even just studies across the general population as well as in animals, is to try and separate or dissociate genetic variants from environmental variants. Or let's just say non-genetic because it could be developmental and those can be very successful.
Kevin: It's not reasonable for a given individual to say, this much of my height, or my intelligence comes from my genes and this much from my environment. That's a nonsensical statement to apply to an individual. But it is a reasonable statement to say this much of the variance in height that we observe across our population is due to differences in nutrition. Whereas this percentage of the variance is due to differences in genetics.
Kevin: That becomes interesting because there's not a right answer to that. You may have some populations where there's lots of variation in nutrition and that becomes a big source of differences in height. Whereas other populations where everybody's getting as much nutrition as they want, it's not a limiting factor. Then genetic differences become a bigger contributor to what makes people different in height.
Kevin: So what that means is that the heritability is by definition tracking differences that originate in genetic variation. However, that doesn't mean that there's a proximal biological mechanism that underpins the variation that you see. It could be mediated by environmental behaviours or outcomes like that. All it says is that the primary source of the variation is genetic. It doesn't say that the mechanism by which it is expressed doesn't involve the environment at all.
Kevin: The other thing is that the mathematical models that people use when trying to dissociate genetic variants from environmental variants, often you just have to make an assumption that those two things are not correlated with each other, that there's no co-variance between them. And in fact, we know that that's a simplifying assumption that doesn't fully hold a lot of the time.
Kevin: Things get more and more complicated and, for example, what we see if we look across the population at things like the genetics of educational attainment where the phenotype is just how far does somebody go in education, some of the genetic effects that we see there are intrinsic to the person themselves. But some of them are actually due to the fact that they share genes with their parents and their parents' educational attainment affects the environment in which the child grows up and the social capital that they have, which enables them to maybe reach their intellectual potential, or academic potential, through the educational system.
Sally: But that's not because they share genes, that's because they share a family environment.
Kevin: But partly the reason they share the family environment or the reason the environment is the way that it is, is partly due to the genetics of the parents.
Sally: I don't know how you cope with all of these different things, it seems that everything affects everything else.
Kevin: Well, yeah. People try to tease these things out and put exact numbers on them. My own feeling is that trying to be too exact about it is pushing it further than we should. You can get a broad sense that some variation in these traits is down to genetic differences and some of it is non-genetic.
Kevin: You can use some of that knowledge to try and tease out what the non-genetic components might be. Maybe they're developmental and still innate to the person, and maybe they're really experiential or environmental. The way I think about these kinds of analyses is as tools to broadly get at those categories. I don't really get too hung up on whether something is 35% heritable or 45% heritable. Those aren't real things. They're highly dependent on the population you're looking at and all kinds of assumptions.
That was Kevin Mitchell, and you can listen to the rest of the interview in episode 14.
S522: Little shop of genetic horrors - the evolution of carnivorous plants
Sometimes when I’m interviewing researchers for these podcasts, they’ll say some throwaway remark that just begs to be explored deeper. That was certainly the case with Ulrike Bauer from our recent episode about carnivorous plants; Little Shop of Genetic Horrors. We were chatting about how pitcher plants catch insects in a different way to sundews or Venus fly traps, and Ulrike just casually said this…
Ulrike: People are always like, "does the lid close when it's captured something?" With one exception, which has moving parts, there's no moving parts in pitcher plants.
Sally: Which one has a moving part and which part moves?
Ulrike: So there's one species in Borneo where the lid moves. It doesn't actively move, but it acts as a spring, almost like an inverted springboard. So when a raindrop falls on the top of the lid, it causes a really fast and really vivid vibration, which kicks the insect that sits underneath the lid into the pitcher.
Sally: So a little insect is trying to get shelter from the rain. It's got a fairly good footing, but then a little bit of a jiggle and it falls in.
Ulrike: Exactly. And the fairly good footing is a good point because you basically need three things for this to work. We've just done a bit of evolutionary work, which isn't quite there yet to talk about, but we've done a bit of work on showing how this can potentially evolve.
Ulrike: You need three things to come together for this mechanism to work. You need a lid that acts as a spring. It needs mechanical properties that turn it into a spring so if you start flicking it, it actually jerks and is sucked into the trap.
Ulrike: You need a special surface coating underneath that needs to be a little bit slippery because insects are really good at holding onto smooth surfaces. If you see flies walking up glass windows, you know that they are really strong at holding onto smooth surfaces. So you need this specialized surface that makes it a little bit more treacherous so if you flick it, the insect's likely to fall. But it needs to be grippy enough that the insect can actually go there and hang upside down in the first place. Because if you can't access this, you don't trap anything.
Ulrike: Then the last one is trivial. You need a lid that is more or less horizontal because if it's at an angle, your insect still gets kicked off but it doesn't land in the pitcher, it lands next to it. So you need to get the direction right as well.
Ulrike: There's this one species in Borneo that has all of that nailed. We've got a couple of research papers published showing that it contributes to the trapping of this species, if you mess with that mechanism, it doesn't work anymore. If you take any of these contributing elements away, if you wipe off the surface coating, or if you mess with the spring, then it doesn't work anymore. So you really need all of these things.
Slow motion black and white video of ants falling into pitcher plant when rain hits the lid
That was Dr Ulrike Bauer from the University of Bristol. You can listen to the rest of the interview in episode 22.
S5.18: The Genesis Machine
In September, Kat interviewed Amy Webb and Andrew Hessel about the future of synthetic biology and genetic engineering in episode 18, The Genesis Machine. They discussed all sorts of sci-fi possibilities such as what would happen if someone hacked into the computers of a DNA synthesis lab and created a cyber biosecurity incident. Or a restaurant that served lab-grown meat from endangered species. But despite all this futuristic thinking, both Andrew and Amy think there’s a lot to marvel at in the present day…
Andrew: We've only had molecular biology for a few decades. The human genome, our code, was just read and we didn't put the last dot on it until earlier this year. But really the publication was in 2003. We've made incredible strides very quickly, but there's so much further to go. Right now the bottleneck in my world is that it's still really expensive and slow to make larger segments of DNA.
Andrew: As soon as we get past that bottleneck and get a thousandfold or greater improvement in price performance, that's the game changer. Because now Amy can literally say, "Make me a vaccine, I'm going to Brazil. I need updates," and a home printer will just make the various constructs. Her body is the manufacturing plant.
Amy: I think so much of biology has become invisible to us. We stop at a Rite Aid, a Walgreens, or a drugstore to get a flu shot or to get a test. That the process that's involved in sending, recreating, reading and synthesizing, all of that stuff has kind of become invisible to people.
Amy: For that reason, we don't really stop and marvel. We don't consider. We have lost our sense of awe. I think that is both a shame and also going to potentially be a problem for us going forward. Because what it's going to start to feel like, little by little, is that these innovations are coming out of nowhere. That they're suddenly here.
Amy: Nothing in science is suddenly here, as all of us know. It is the result of the compounding effect of hours, days and weeks spent in labs, researching and learning and all of these other things. But we're moving into this era where change is gonna start feeling faster than is going to be comfortable to us. The way to get comfortable with the uncertainty that's ahead is to just keep your eyes open to signals in the present and to be contemplating what's happening.
That was Andrew Hessel and Amy Webb, and you can listen to more in episode 18
Image credit: Anne Weston, Francis Crick Institute
S5.05: Sex and the Single Cell
We like to bring you not only interviews on this podcast but also longer stories where we can really get stuck in to the nitty gritty of a topic. This year we’ve looked at the genetics of faces and fingertips, Turing patterns and junk DNA, the random wobble, cannibalism, bees and behaviour to name a few.
Way back in March in episode 5, Kat looked at the secret lives of cancer cells telling the story of how scientists first discovered that cancer cells could have sex, which she originally wrote for the online science magazine Neo.Life. Later on in the year, the Medical Journalists Association awarded Kat the Gordon McVie Award for reporting cancer research for her article, describing it as “innovative, intriguing and very cleverly written”. Needless to say, she’s very proud of it, so we’re going to play it again in all its glory…
That’s all for now and all for 2022! Thank you so much to all of our wonderful guests who have been on the show this year. Plus some extra thanks to people we don’t usually mention: to the Genetics Society for financially supporting Genetics Unzipped; to the Genetics Society committee, especially Jonathan Pettit, Alison Woollard and Cristina Fonseca; and to everyone in the team at First Create The Media who works on the episodes from the researching to the website with an extra big shoutout from me to our fabulous editor Emma Werner.
We’ll be back in the new year, but until then, as always, if you want more information about this podcast including show notes, transcripts, links, references and everything else head over to geneticsunzipped.com You can find us on Twitter @geneticsunzip and please take a moment to leave us a rating in the Spotify app or review us on Apple podcasts - think of your rating as a little holiday gift to the Genetics Unzipped team!
Genetics Unzipped is written and presented by me, Sally Le Page, and Kat Arney. It is produced by First Create the Media for The Genetics Society - one of the oldest learned societies dedicated to promoting research, training, teaching and public engagement in all areas of genetics. You can find out more and apply to join at genetics.org.uk. Our theme music was composed by Dan Pollard, the logo was designed by James Mayall, and audio production was by Emma Werner. Thanks for listening, and until next time, goodbye.
