Briefing Chat: Can NASA return rocks from Mars? And why dogs have long ears

0:03Hi listeners, Benjamin here. Welcome to the first episode of the Nature Briefing podcast. Now, if you heard the main Nature podcast on Wednesday, you'll know we're spinning the briefing chat section out into its own show, which will go live on a Friday. And we'll talk about a couple of stories that we've read in the Nature Briefing, which is Nature's daily roundup of the latest science stories. And talking with me today is Nick Petrich-Howe. Nick, how are you doing? I'm doing well, Ben. Thank you for having me on our first one of these briefing chat shows. I'm excited to get into it. Well, I'm excited too, and we've got a couple of really great stories.

0:40First up, we've got a story, well, perhaps it's the conclusion of a story, and it's about getting samples back from the surface of Mars to Earth, and this is a story I read about in Nature. So yeah, this is something we've been talking about for a while in the podcast. Obviously, many scientists keen to get their hands on this. How is it all going? Well, this is one of those stories that I think is perhaps not entirely unexpected, it has to be said. But how it's gone over the last few years is, of course, the Perseverance rover has been rolling around the surface of Mars, collecting rock samples since 2021.

1:15And as we covered on the show, I mean, it stored many of these in its belly and also deposited some on the surface. And there are 40-something sample tubes, Nick, most of which are filled with different types of rock. But the problem has always been... How do we get them back? Yeah, they're a long, long way away. And how do we get them back to Earth? a massively ambitious project, and one that would be massively expensive. In 2023, we ran a story in Nature suggesting that it could cost$11 billion, which would be similar to the cost of building the James Webb Space Telescope, the JWST. And about a year ago, NASA said, well, we've got a couple of plans.

1:53We're investigating some paths to go down, a way to save some money, sort of kicking the can down the road. And that brings us to something that happened last week. Okay, so what happened last week? Has the can finally hit the end of the road? I think the can has struck the end of the road. So last week, a bipartisan group of US lawmakers passed a spending bill which axes the return programme. And a lot of scientists, I think, were obviously disappointed because there are, of course, a lot of questions that won't be answered as a result of not having these rocks. Yeah, right. I can imagine that they're disappointed.

2:31So has there been any alternatives proposed or is this dream sort of dead with this? Well, it might not be dead, but it's certainly on life support, I think, at the moment. So the spending bill that has resulted in this sample return mission being cancelled does actually contain some positives for space scientists. It has restored funding for the majority of NASA space missions that were on the chopping block by budget proposals from the Trump administrations, including the Habitable Worlds Observatory, this space telescope that's going to search for signs of life. But also, this bill, which still requires Senate approval, it has to be said, does set aside$110 million for the NASA Future Missions Program, which will continue to develop some of the technologies that were being investigated for the sample return.

3:22So if it's decided that this becomes a priority in the future, this has kind of been ticking along, I suppose, in the background. So if they are able to figure this out, what sorts of questions could they answer by getting some samples back from Mars? The biggest one, of course, is, is there life or has there ever been life on Mars? Which is a massive question for humanity. And looking at stuff from there is the only way to do that currently. And there is this tantalising sample that the Perseverance rover collected. And last year, NASA announced that it had found these spots on a rock. They were called leopard spots.

3:57I think we might have covered it on the podcast. And this rock contained chemical compounds that are found on Earth produced by microbes. But the other side of it is they could also just have been produced chemically, so not life at all. And there's a sample that was taken from this rock, Sample 25. And obviously, researchers are so keen to get their hands on Sample 25 to find out which side of the coin was it. Was it life? Was it not? But there are other things, too, Nick, as well. if humans want to step foot on mars it'd be good to have an idea of the conditions there we know some things of course we know that the soil contains toxic perchlorate molecules for example we know that the soil is also electrostatic you covered it on the podcast yourself right yeah lightning can exist but what else is going on there and i think if humans want to work safely it'd be good to know that and there are longer term questions as well you know about mars's origin story, its backstory, you know, how it was made, how its crust formed, you know, geological questions, these processes that take eons.

5:00Now, this has been done on the moon to kind of figure out some more information about our closest neighbour. But yeah, there are lots of questions about the red planet that researchers want to ask and answer as well. Well, yeah, I think knowing a bit more about Mars before we eventually go there probably is a good idea. And we'll keep an eye on this story as it develops and if NASA or anyone is able to figure out a way to get these samples back but I think we can move on to my story now and it's a story that also started with a curious question but the question was in this case why are some dogs ears so long right because some dogs have long floppy ears I'm thinking of what a basset hound obviously others have the short pointier ears and I suppose I've never thought why is one like one and the other like the other but it seems researchers have done right well it seems that researchers have only just thought about this because this was actually inspired by a cocker spaniel it was a cocker spaniel that belonged to an undergraduate who was looking at canine genetics and they wondered why does their cocker spaniel called cabane have such long ears and it turns out we didn't actually know so i was reading in nature about an investigation into the genetics behind why some dogs ears are long and floppy and why some are not.

6:19I really want to know the answer to this Nick how did they go about it then? Well it will not surprise you to learn that to understand the genetics they looked at the DNA from a lot of different dogs in fact also wolves and coyotes as well so they looked at more than 3 ,000 dogs wolves and coyotes and then they looked for associations between changes to genes and different lengths of ears and what they landed on was a gene called msrb3 and it wasn't this gene itself but there was some dna variants near this gene that seemed to be associated with the ear length in dogs right and what do researchers know about this gene well we know some things about it so in the past mutations in this gene have been linked with hearing loss in humans and it's also been associated with the carriage of dog ears and what i mean by that is do the ears like point upwards do they lay flat are they floppy are they not so floppy that's what carriage means in this case so the gene itself codes for an antioxidant protein and it's also been linked with ear size in pigs sheep and goats so it looks like the variance around this may have boosted its activity which could have made the ear cells proliferate more so more activity of this gene more ear cells proliferating more ear so the team put forward this evidence then of this biological phenomenon that i guess we see all the time when we're out in the park or whatever but nobody had thought to ask yeah so things like carriage like i said the sort of pointiness or floppiness of theirs that's been looked at before and other things to do with dog genetics have as well but length seems like an unexplored thing and you know as you mentioned that we do see it in various different dogs around part of that is due to selective breeding so in the basset hound that you mentioned it's been thought that the long ears allow sense to go closer to its nose and allow it to be able to track sense better because it was used for tracking down things when people were hunting and other parts of it are also to do with adapting to different climates so canines from cold climates tend to have smaller ears than those from warmer regions because it's thought that they lose less heat from the smaller ears so this is putting a genetic explanation to that it's not the end of the story though it's likely that there are other changes this analysis focused on single letter changes to the dna but it could be other things such as large deletions or duplicated regions of the genome that could also be at play here and one of the researchers interviewed for this said that a good place to look next would be at golden retrievers because golden retrievers i don't know if you ever noticed this they have a lot of different ear sizes and lengths so if you can constrain the analysis to just one breed you may be able to get a better understanding of the specific genetics at play here right do we know what cobain the dog thinks about this about knowing a bit more about their ears i'm not sure but i think it's a nice story often in science where someone just asks a question and then they're able to actually go and figure it out and this as i say came from an undergraduate called anna ramey and she just looked her dog's ears and thought why and you know that's science at its core i think fantastic well let's leave it there for this friday's podcast we'll put links on where you can read those stories in full in the show notes and a link where you can sign up for the nature briefing to have even more stories like this delivered directly to your inbox as always you can keep in touch with us on social media we're at nature podcast or you can send us an email to podcast at nature.com i'm nick and i'm benjamin thompson see you next time