Africa, South Africa, Equatorial Africa discussed on Morning Edition


In fact, we estimated maybe only three percent of the croissant. Population was sort of replaced by these East African pastoralists who are very very low migration rate and then subsequently. Around a thousand or fifteen hundred years ago, you have the dispersal of Bantu's speaking agriculturalists who also move into southern Africa. So they have crops with them their farmers, and they're primarily looking for areas, which are good for growing grain. And they move into the eastern part of South Africa, initially, and then they spread throughout southern Africa. You now bring to this story. The fact that the choice on people in southern Africa have a lighter skin tone than Africans from other parts of Africa, and you're able to dig into that by using genetics. That's right. So it's been observed for a long time that the quiz on a have relatively light skin pigmentation compared to many populations that live in Equatorial Africa or eastern Africa. What we were interested in is trying to identify. What is the underlying genetic basis for light skin pigmentation, and of course, on and then if we can identify those Sheens can we actually modeled Lucien of skin pigmentation. So when when did light skin pigmentation actually evolve in the croissant, and it turns out to be a very complex trait? More than fifty genes are involved. So we decided just to focus in on one of them. This was the one that really had the biggest signal, and it has a name SOC two four eight five a bit of a fancy name not to worry about that so much. It's really well characterized, gene. Because in fact, it's the same gene, which has been identified in Europeans as also contributing to light skin pigmentation, actually the same. I'm trying to work out is actually has the has it migrated from European itself. So we'll see two a five this chain has been very well characterized previously. We know today virtually everybody. Of western European ancestry carries the derived copy of this, gene. It's at ninety nine percent frequency and Europeans. It's also very frequent however in the near east so people of near eastern ancestry. Also, carry this, gene close to one hundred percent frequency, and we know that there have been back to Africa migrations associated with the invention of agriculture and pastoralism. So at some point in prehistory, maybe five thousand years ago ten thousand years ago, it's not very well dated a group of individuals from the near east who were agriculture Lous and pastoralists they then migrated back into Africa. And with them. They certainly brought this C two four eight five Lille. There are two things. I really love about this one is kind of stories you can tell by looking at genes of people thickness at the happened thousands of years ago. And also just how much people were able to move way back then. And it's not necessarily that. There is vast numbers of people moving is that a little bit of migration can actually introduce novel mutations into another population. And you don't know what's going to happen. I mean, maybe they'll be under selection. Maybe they won't, but this novel variation is the is the basis for evolution. Brennaman geneticist from the university of California at Davis. The study was published by the US National Academy of sciences early this week. So it was sex mutation that spread that gene from the northern hemisphere to South Africa, and that's the power of sex in eve, Lucien jeans, get mixed up and the best ones contribute to long-term fitness for plump previous though sex can be a bit of a pain having developed a really strong hybrid crop variety. They find their hard work diluted by over random jeans. Brought in by pollination that's white so many f one hybrid seeds Ron sale they have to keep going back to pure varieties to keep the strain at his peak. This also white so many crops are propagated clones. Typically as cuttings. The clones all have the same strong genetic mix. So another project coincidentally at the university of California Davis is working on developing seeds. Seeds which all have the same jeans is the plants they come from working, I own REIs not global staple of our diets to tricks needed the first to make sure the grains have a full complement of all the genes without there being any pollination and second. Well, the pollen comes with chemical signals, which triggers the development of seed is team leader vinca and raise told me what we discovered this among the very first jeans to be switched on higher bunch of these genes called transcription factors, richer muster regulators of other genes, and among them, the one that stood out this number one is baby boom, basically, boo. Let's say it's a great name. It had been discovered not by aspect where another group can put in the Netherlands who should many years ago. Teddy few switches, gene, Autry in property start making embryos. What's really interesting is that this gene kept silent in the exile. And it's a sperm cell. It provides missing the XL got almost everything it needs to make an embryo, but it can't do that kisses missing trigger which sperm so provides. So you able then to use his factor without having the sperm without having the pollination event. That's right. We make the male basically redundant this process. The reason that if this is all the XL needs to kick off the process, but let's do away the male just give it to the exit directly. And that's what we did you go way there to kick off the development of the seed, but in a normal plan for female part is sort of waiting for extra genes to come in from the male sperm, which are no longer there. So you doing something about the developments of female part of that rice plant so that it can develop itself directly into a seed there's a process by which they female germ salary. Excel gets rid of. Half the DNA, and we'd block that process. So that the allow has a full set of DNA from the magic, it's technically genome editing. So how far have you managed to push this? Have you got actual seats? Have you got viable plants from those seeds? Fully function plants from which we called clones because they're genetically identical to the mother plant. Clones produced grand clones, which their also identical. And then the grandparents have in recent months given birth to great grand. Clones, we know that this new creative heritable it's transmitted to children and two grandchildren. So stay generations of are plant biologists to lots of clone all propagation, which is where they'll take some cells or a little bit of leaf or something like that and plant that and you'll get the same plant growing again. But this is interesting because you're not doing with plant parts, but with effectively clone oil seeds is that right? And seats are wonderful. You can store them for a long period of time and plant wish. Every wish so convenient package of genetic material. So the advantage then of this clone oil seed would be that you'd make a hybrid which had no high vigor or had drought resistance or something like that by making all the plants make clones of themselves through their seeds, you preserve all those qualities down the generations through the years too much to pretend rations have you mentioned do they say with shall we say laboratory samples of rice will have you done this with those kinds of varieties of rice that people would really like to plant what we've done with the variety of rice that's grown in northern Japan. It's quite a very short generation time. So it's much easier to work with but the principle is that these genes that we worked with her found in in all rice. There's no reason to think it wouldn't work with any of them. In fact, I would go further and say in all Syrians in all cereals. So what you've done with rice. You could do with. Maize and you could do with wheat and other zero crops as well. Yes, we are pretty confident of because the genes are highly contract across the females people. Sometimes get worried about monocultures they're very susceptible to diseases. And so on does this kind of clone propagation make crops even more vulnerable is that gonna be one problem? That's a great point. What it want to do is not have something that only one variety of hybrid. And that's why I think feed companies would still need to be pretty soon different types of hybrids. That's already a case in India, for example, less than ten percent of the advice exploited his hybrid has competitive person in China, but they have developed hybrids for different parts of India for the north and south and so on which are better at actors conditions. So you don't want to limit yourself to one hybrid. And should keep developing either luncheon reserve now the monoculture problems arise especially with wrong lived, don't even so they actually from the saints talk like bananas or even cacao these are seats. So these are not from rootstock are vegetative, partly cloudy. So it's much easier to switch over as long as you keep producing different varieties of hybrid. You should be able to guard against it. Eventuality palm geneticists vancomycin Senator as of making the males of the species somewhat redundant in grain crops, at least be very interested when this stops moving into field trials, but these first steps are described in nature this week, you can find a link to the page. On the science in action webpage at BBC World, Service dot com. And we finished with plants and the whole truth about climate change greenhouse gases have been climbing since industrial revolution and client past four hundred ten parts per million just this year levels not seen since. Well. That's the question. No one was measuring CO two in the past. And that's where those holes come in there. The pause or STA Marta in leaves which let plants breathe during photosynthesis. And which change according to the amount of CO two around this money Chesterton has been hearing. I've got a method that will enable us to estimate carbon dioxide levels. All the way back to the earliest land plants with STA so that's over four hundred million years ago when the carbon dioxide level increases plants are very clever. They can get the same amount of carbon by having fewer STA Mata on the leaf surface. They lose less water. So they become more competitive compared to their. Labor. What all of this means is to find out. How much is in the atmosphere at any point in the earth's history. You simply have to find a fossil leaf from that period and count the number of STA on it. Well, I say simply that sounds like a lot of very painstaking work, and ideally, you need plants with a very long history on earth, send the little plastic bag here you can lift that up and the sun will probably be beaming through and you'll see the nation on the leaf, and it's two hundred million years old. Wow. Being eaten by a hibiscus dinosaur. That's how that is. And they are gingko leaves. So a lot of people would know kinko's beetle species. So what we have to do the fossil is we have to work at what species is that fossil. And if it's still living we calibrate how the numbers D'amoto change in response to changing carbon dioxide levels using the same species. So gingko around today is it pretty similar two hundred million euros ginko, the whole leaf looks very similar the stairmaster look very similar, but there's a big difference in the number. It's democracy. So today, a modern Kinko we'd probably can't about ninety two hundred stairmaster at the top of the pinhead. If we then counted the numbers D'amoto on the fossil we would find any back twenty to thirty. And that tells us that the fossil gingko two hundred million years ago was growing in a carbon dioxide level. Three. Three to four times higher than it is today so much more elevated than today that's past and present what about future plants Jenny takes me across town to.

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