Could Jurassic Park be a reality? How did dinosaur blood survive for 65 million years? Why is volcanic gas poisonous? Is astrology scientific? What is the Universe expanding into? Chris Smith joins Aubury Masango to answer your science questions...
Aubury - Scientist Good morning to you Chris. Thank you very much for joining us I really appreciate your time sir.
Chris - Morning Aubury!
Aubury - So I saw that that you guys have now come to find out what the DNA of dinosaurs might have looked like.
Chris - Yeah this is a very interesting paper by researchers at the University of Kent out in the journal Nature Communications this week. And what this group did was to not look at dinosaur DNA itself because dinosaurs disappeared from the Earth about 66 million years ago or so, and we think that what prompted them to shuffle off the planet was the arrival of a very large asteroid, which smashed into the earth's surface in the Gulf of Mexico and caused enormous climate change and dinosaurs were unable to evolve fast enough to cope with that. So they went extinct. But they have left their legacy behind on Earth because many people who are palaeontologists will tell you that in fact the world is still full of dinosaurs because they're all around us all the time in the form of birds, because birds are the closest descendants of dinosaurs have on Earth today. And that's because one group of dinosaurs, as dinosaurs evolved turned into winged creatures with feathers that could fly and they were the direct precursors of the birds we have today.
So the point that Becky O'Connor and her colleagues are exploring from the University of Kent is if we look at the genome structure and the DNA structure of modern birds we can probably learn quite a bit about dinosaurs. But then what we dont know is well, has that changed very much in the 66 million years since the dinosaurs went extinct and in the modern day how would we know if birds really have a dinosaur DNA-like structure or whether or not it's changed. The way they've got around this, very intriguingly, is to say well when did animals on Earth today last have an ancestor that they shared with the dinosaurs. And it turns out that turtles and reptiles and therefore birds all have a common ancestor way back in evolutionary history about 250 million years ago. They haven't shared any ancestors since. So if we look at the genome structure of a turtle, if we look at the genome structure of a reptile, and we look at a bird then we can ask "well in what way are they similar or different?" And the really extraordinary thing is that they are really, really similar. Turtles and birds have really similar DNA organization and in fact they've got more than 30 chromosomes and they've got some really big chunky chromosomes that have quite a few genes on them but then they've got lots of these miniature micro-chromosomes have very few genes on. So because turtles have that, and because birds have that, and they would have shared an ancestor before the dinosaurs came along that tells us the dinosaurs must have had that too. So we now have a really clear insight into the arrangements of the chromosomes in dinosaurs, and therefore how the genes would have been organised in the dinosaurs as well because they've been able to compare the two. So it's almost like a molecular post-mortem going back a quarter of a billion years and we now have an insight into how an animal that no longer walks the Earth would have organised its genetic information which is extraordinary.
Aubury - Chris, I suppose for science's sake, you know for the advancement of knowledge we want to know all these issues, but you know a few years ago they made this movie the Jurassic Park. Are we perhaps anywhere close to making Jurassic Park a reality?
Chris - Regrettably not. Michael Crichton made millions by writing Jurassic Park and it really captured the imagination because the time when Jurassic Park was made and written and then turned into a book coincided with a technological revolution in molecular biology. We began to gain new insights into how DNA works, how our genomes work. And we began to engineer DNA and change the behavior of cells and even whole creatures. People were reprogramming bacteria to make say human insulin so that we were no longer needing to take insulin from animals to treat diabetes. So there was enormous enthusiasm at that time and it fueled imaginations of people like Michael Crichton. The harsh reality is quite different which is that dinosaurs haven't walked the earth for millions of years the longest we can wind back the genetic clock and get DNA from fossils, at the moment the largest, the the furthest back published evidence for this, Eske Willerslev who's a researcher both from the University of Copenhagen and the University of Cambridge. He holds the record at the moment for sequencing the oldest DNA, his DNA sequence goes back more than half a million years he sequenced the genetic information of a horse from half a million years ago. We have not succeeded in getting any older DNA samples yet but given the quality of work that's being done around the world, given the quality of preservation of some fossils that scientists are now finding including in South Africa, I would watch this space. We may see that number go back, significantly, in the near future but I dont think we're going to get it back to the point where we'll have real dinosaur DNA or DNA sequence. And from that we would, we could compile a real dinosaur we're not going to do that any time soon.
Aubrey - I go now straight to the lines. Shane in Randburg Hi Shane.
Shane - Hi Aubrey and Dr Chris.
Aubrey - Go for it Shane.
Shane - Sticking with the dinosaurs, a couple of years ago, I think it was Dr Mary Schweitzer from the University of North Carolina discovered some tissue and blood in a dinosaur fossil.
Aubrey - Yeah
Shane - And from dating methods etc. that's not supposed to be possible. Obviously these are carbon lifeforms which are not supposed to look for beyond let's say fifty or sixty thousand years.
Aubrey - Yeah.
Shane - And my question is whether they've come up with any plausible theory explaining how carbon lifeforms can be preserved for 66 million years.
Aubrey - Yeah. OK. Shane. Dr Chris Smith?
Chris - Hello Shane. I've met Mary Schweitzer, who is the person who published the paper in the journal Science. It was in about the year 2004 or 5 she actually first published it. She told me that what happened was a bit of a mistake. She had some T-rex fossils. She was trying to examine them chemically, so she put them in a solution to remove some of the rock from the sample to dissolve out some of the minerals that these fossils were made from; she forgot about it came back into the laboratory a few days later and discovered that, in fact, rather than just falling into dust where she'd removed the minerals there was some kind of tissue matrix left behind and so she speculated in her paper that this could be original dinosaur protein material, or something like that. Looking down a microscope she saw structures that were very reminiscent of what she thought might be blood cells; therefore she decided to try to extract some genetic information from the samples.
She did extract some genetic information and also some protein and what she was able to do was to compare the genetic sequence she got from those samples with the DNA of existing dinosaurs called birds! She also did this for the proteins and this led to speculation that, perhaps, inside a fossil there might be real tissue preserved and that we might be able to get genuine genetic information from this. This has subsequently not been repeated. I haven't seen any evidence corroborating these findings. Since then, some people have speculated that, in fact, because it's so easy to contaminate these specimens with modern day DNA that, in fact, that might be some of the explanation for what she claimed to have discovered. I think if this were likely to be that easy to do, people would have replicated it and replicated it in large amounts; but it has been ominously quiet ever since she published that paper. So I'm not saying it's not possible, but I'm not saying it's easy either. So we do think that we're on the same page as you, which is scientists think that the damage chemically that happens to a molecule as it ages over millions of years just means that eventually there's nothing of any value left behind that actually is chemically meaningful. There's just rock.
Aubrey - Lueda in Ontdekkers Park, hi.
Lueda - Good morning to you. Thanks for taking my call.
Aubrey - Sure.
Lueda - Right now there's a volcano erupting and some poisonous lava flowing into the ocean. Why is that? Why are those gases poisonous?
Chris - Well good morning. Yes, you're referring to the eruption that's happening in Hawaii. Hawaii is on a hot spot in the Pacific Ocean and this is where there is an upwelling of magma. The hot runny rock from inside the earth is close to the surface and it's been erupting there for hundreds of years. In fact, Hawaii has one of the world's oldest volcanic monitoring stations. It was first started more than 100 years ago and that's how long the eruptions have been going on. The current eruption is happening on Kilauea, which is the big volcano on the big island of Hawaii. And in recent weeks, certainly at the end of April, things began to change because where there had been this lava lake which had a level of lava rising and falling regularly like a metronome. And there was also another fissure which was just gently oozing lava on a regular basis. This suddenly changed and the level of lava in the lava lake plummeted. It's gone down three hundred meters now actually and the fissure that was issuing lava stopped and then these new cracks began to open up. And earthquakes began to happen and then this lava began to emerge from a new site in the middle of a heavily populated area which has caused the current crisis. Now what's actually happening underground is that as this hot magma comes to the surface it is decompressed. So when it's inside the Earth it has the mass of all the rock above it on it and it's under enormous pressure because the inside of the Earth, it's very hot. It's also confined. So there's very high pressure. This means that a lot of gases and other things dissolved in the hot lava. When it comes to the surface it can expand. And this means the gas can escape. Those gases include sulfur compounds like sulfur dioxide and hydrogen sulfide. They also involve, they also include, include carbon compounds like carbon dioxide and carbon monoxide. There are also oxides of nitrogen and other exotic species and possibly cyanide and things in there as well and things made locally in the high temperature chemistry that's going on when the lava emerges.
These chemicals if they're present in high enough concentrations won't be blown away fast enough to avoid poisoning people. And there have been many accounts in the past of when there's been an eruption, these chemicals will very quickly rise in concentration, locally. Many of them can be heavier than air. And so if the local geography means that you're living in a sort of bowl where actually you're below the level of the surrounding land then these gases can flow like water into a lake and they'll settle there and they can asphyxiate people and they've been very many documented situations where, say gas, is dissolved in volcanic lakes can suddenly erupt up to the surface spill over and and drown a community in carbon dioxide for example. So these gases are not pleasant. They do damage to you in various ways some of them are very oxidizing, carbon monoxide asphyxiates you because it locks onto your hemoglobin the pigment in your red blood cells that carries oxygen around your body and it stops the red cells carrying oxygen so that your tissues effectively asphyxiate. If you have carbon dioxide you can't get oxygen in because the carbon dioxide gets in the way of the oxygen getting into your lungs and in your bloodstream. So there are all sorts of many different ways that you can be poisoned by these things so volcanoes are beautiful, they're impressive but they're also incredibly dangerous.
Aubrey - I've got an SMS question here for you. Good morning all, Dr Chris I'm being treated for a prostate problem and have urine bag for the past six months. Can you please advise what foods are good to improve the function of the bladder? I am a male aged 77 I'm not really sure whether that makes any sense to you, Dr Chris?
Chris - Yeah unfortunately it's a fact of life of being male that's about 100 percent of people will get an enlarged prostate as we age, the prostate is the gland that sits around the neck of the bladder and it has a number of jobs to do. But one of them is to make various secretions which are added to seminal fluid but it responds to hormones like testosterone and this has a growth effect on the gland. And as you age, because your prostate cells are seeing a long term exposure to testosterone, they proliferate and everyone gets a growing prostate with age and this is called benign prostatic hyperplasia. As the prostate gets bigger, what it does is to encroach on the neck of the bladder. So the pipe which carries urine out of the bladder which has to pass through the prostate can become squeezed on one particular part of the back of the prostate gland can end up projecting into, or blocking off, that urine pipe, the urethra. And this means that can become harder to pass urine so the bladder has to become bigger and more muscular, and this can cause problems because you can end up with urine not completely leaving the bladder so you end up with a residual volume, and that can encourage infection. And there are luckily a number of treatments some of them you dont actually have to do anything to the prostate, but you can take some drugs that can help things in other circumstances sometimes it's helpful to remove some of the prostate tissue to make it easier for the urine to leave. In all cases doctors will do the most minimally invasive thing they can get away with doing. But one consequence of this is that you can get some bleeding you can get some infection and may require a catheterization for a while which it sounds like has happened to this person. In terms of what you can do to minimise the risk of this happening, the answer is theres not a lot you can do. Its a one consequence of age, if you start to spot the symptoms you should seek medical advice promptly because there are a number of reasons why this might be happening not just benign ones. So its worth getting checked out to make sure that there's not something more nasty happening, and also intervention before it becomes a serious problem is likely to have a better outcome than intervention if you leave it to you've got serious problems, but because its a bit embarrassing people often dont mention it they suffer in silence for a very long time before they then get sorted out. So seek seek advice promptly.
Aubrey - Indeed. Quickly take a call from Esther in Pretoria. Esther Hi. Esther?
Esther - I just want to the reasoning of astrology and numerology and cosmic cycles, psychics use it. Is it real or not. Is it scientifically real or not.
Aubrey - Dr Chris astrology numerology is a real is it scientific?
Esther - And cosmic cycles, yeah?
Chris - Yeah hi Esther. In a word no. In terms of astrology. No there's not really any evidence supporting any of this. But the thing is it makes people happy. And there is evidence supporting the fact that if people feel happy there's a placebo effect. So that's part of it. In terms of understanding how the heavenly bodies move though this was used for various purposes in the past because people who discovered how the heavenly bodies orbited had an enormous advantage over other people because they could make predictions about what was going to happen and then they could look really impressive so they could say to people "I am very powerful in three weeks time there's going to be an eclipse and the moon is going to disappear and I'm going to make it happen." They knew this because they plotted the movements of various celestial bodies and they knew it was going to happen. It would therefore make them look very very impressive and everyone would be wowed out when of course the moon did show an eclipse, and they would think this person was terribly scary and terribly important. So it was used as a way of deceiving people into having respect for people. But there's no scientific justification for a lot of this stuff.
Aubrey - All right very quickly from Bahcausy. Good morning to you sir. Apologies go ahead. Yeah often expenses. Yes.
Bahcausy - Yeah, Mine is about the theory of the expanding universe, what is it expanding into? Secondly, we are told that there are billions of galaxies in the cosmos. What are the possibilities of them colliding and what are the consequences?
Chris - Hello Bahcausy. Right, so the first question is the universe is expanding. What is it expanding into? Well the answer is we don't know. The universe is everything. If you take that definition then the universe isn't expanding into anything at all because it is everything already it's just getting bigger in terms of what's out there in the rest of the universe, we're in one galaxy that's the Milky Way galaxy. We think that there's something like a hundred billion other galaxies a bit like our galaxy elsewhere in the universe. And yes some of them are on a collision course. For instance the Milky Way our galaxy will collide with the Andromeda Galaxy which is moving towards us fairly fast pace in a few. I think it's a, thirty, four billion years time. I think we're going to collide with Andromeda so we won't be here to see it but it will happen. Now when these collisions happen then gravity will be the king because there will be the meeting of different entities which are moving in different directions at different speeds. They will dissipate their energy and some planets will be captured some stars will be captured they'll form some new aggregation of material which is, the structure of which will be governed by the gravitational effects of the merging of all of that material. Some things will just carry on straight through out the other side because although, although we think of galaxies as a condensation of stars and indeed they are there's a lot of empty space in there so just because a galaxy goes near our galaxy doesn't mean we're going to have a huge great collision in space, but we certainly will see a reconfiguration of of those two entities when they pass through each other.
Aubrey - Dr Chris I want to thank you very much for your time we've run out of time and thank you so much. As always we appreciate it.
Chris - Thanks Aubrey. See you soon everyone. Bye bye!