 But I wanted to talk a bit about evolution because this is something that I study in the Lab of Giuseppe Testa. I start from very far, from what not a human is, but something very similar, which is, so when I talk with my friends about evolution, the first thing that comes to mind to people who are born in the 80s and in the 90s is Lucy. Lucy has been called the missing link between humans and monkeys. There's still a big fuss about creation and evolution, but let's fake that we all believe in evolution today. And basically for two million years, at least, there was a place in Ethiopia in Africa where there were these creatures who had some features that are very similar to humans and some that are decently similar to chimps. But basically I want you to keep in mind that these two individuals that we found in Ethiopia had erect walking, so they have a structure, their bones of the legs and their pelvis was in such a shape that allows for walking. And they also had a less pronounced snout, so a smaller mouth. I want you to keep in mind this for less of the talk. And also they didn't have these dagger-like canons that we see in chimps. So they had smaller teeth, a smaller face, and they were able to walk. So this is, I think, the first set of features that you can think about when you want to define what a human is. Long story short, Darwin had a theory of evolution that is basically, it's defined as a tree. So basically there are moments in which population of individuals or elements separate and become kind enough different to not be able to breed again or reproduce and become different enough to be defined as a species. So today we define species more or less, be very vague now. As population of individuals that are able to interpret, so they are fertile, they can have an offspring that is able to give offspring again. So this is a very old picture of human evolution, like a tree again, when there are also species that are not totally believed to have existed today. So it's basically a tree again. There are branches and leaves that go up to Homo sapiens, and they include the astrophotopithecus, which are these two guides here. But the point is, or my presentation is that evolution is not, is a bash more than a tree. So an important concept that also people studying evolution never really quite get is well described in Wikipedia. So I think that we will all be able to keep in mind in the future. Integration basically is a process that happens while two species are starting to exist and elements, individuals from two different species are able still to hybrid, to make hybrids that are able to give offspring. So again, there is this moment during which speciation is happening and genes and variants can flow from one group of people and a group of other people that are supposedly from different species. And this is important because in human evolution these happened many times and we see today, for instance, we all know more or less what Neanderthals are. If you combine all the variability in human population today, the Neanderthal genome is at least 20% of the Neanderthal genome is present somehow in current genomes. So it means that we were able to intermingle, let's say, and have fun together for a certain period of time. And actually, if you look at single individual, we won't have more than 5% more or less of Neanderthal genome in each of us. Maybe less. It's cool because there are shades of amount of Neanderthals that you find in people depending on where they come from because actually Neanderthals evolved in Europe mainly and they moved a bit to Asia but they were kind of absent in Africa, for instance. So you can see really different sub-population of humans that have different amounts of Neanderthals in DNA. And it will be cool maybe with 23andMe to find how much Neanderthal you are. So just to do that. So what are humans? What are humans? The question today is basically how do you define a human? So I think that an important element, set of elements that we find already in Omorectus, which was 2 million years ago, they were already able to run long distances. We know it because of their anatomy, where they lived because basically Omorectus is found in several continents and it's amazing because Omorectus was able to make very complex shapes to shape tools and weapons and the technology they were using in Africa, in Europe and in Asia was the same. So it means that we are able to translate generationally and across populations because you can imagine that these people were not living always at the same time and the same moment they were meeting again after generations and were sharing technologies, making fires, cooking. So I think that a human, at least a proto-human, a very, almost modern human is able to make fire, to travel long distances, to shape tools and share knowledge. Also there are people claiming that the first engraving, so a kind of art, very simple art was already present in Omorectus, but Neanderthals, instead, were the first, or at least together with Homo sapiens, able to make, to use symbolism, so to abstract, to think out of the box, to have art, sort of art, to make ornaments and stuff. I think all of you have played with these shells in the sand, like Neanderthals. There are studies that say that probably most of these holes are made by nature, it's not made by people, but I think you share all of you some aesthetics that were already present with Neanderthals, but for sure Neanderthals have some different aspects with humans, modern humans, that are evident. So for instance we have smaller teeth, smaller jaws, a smaller ridge, a broad ridge, and a different brain case. So and some people have put forward a theory that we evolved by something called self-domestication. So when you look at wild animals and domesticated animals, you often see that between the two there are differences that goes to tooth size, thickness of the jaw, muzzle projection, so much the mouses, and also the shape of the brain case, of course. So the idea is that, like we do with domestication, basically we breed animals to have more less stressful animals, animals that trust more humans, more sociable somehow, and also with certain physical traits, because sometimes we don't select the behavior, sometimes we select the shape, but we don't... So in most of the case when we do domesticated animals, I'm thinking only about dogs, I'm thinking about cows and whatever you... I mean there are different types of domesticated animals, some we eat, some we don't, depends on you also, but basically the point is that these differences, these structural differences are rooted mostly in the neurocrust. So some people try to explain why this domestication happens and appears in humans and domesticated animals, and we kind of agree there is some missing, not so important. So we kind of agree that the cellular reason for why we have these differences in reduced teeth, floppy ears, reduced jaws, white patches in the body, are partially a byproduct of selecting the animals for their behavior and partially for their aspects, but basically there is these cells that are present in the embryo, and they are cool because basically they exist only in the embryo, it's a population of cells that migrate through all the body of the embryo, and they differentiate it because you know that we are made of billions of cells and there are different cells with different shapes and different functions, and many that make up the fascia structures, the bones, the muscles come from the neurocrust. And basically going forward some people said, okay then it means that during evolution and during domestication what happens is that there is a selection for a less active neurocrust, so a less active neurocrust will translate into smaller bones as smaller fascial traits and so on. So the idea is that similarly, similarly to what observed in dogs and foxes, modern humans with respect to archaic samples show milder traits potentially due to this reduction on the neurocrust activity. And one disorder that we study in the lab is William's syndrome, in which we found that basically gene called Baswan B, when it's defective, generates individual with a smaller jaw and intellectual disability, so it amperes both fascial features, body features and intellect. And what we know now thanks to our research is that Baswan B controls a bridge, a switch during early embryo development where the stem cells of the embryo need to decide to go toward the neurocrust or toward the brain. So the idea is that with the lower amount of Baswan B has with respect to archaics and for instance also in case of patients with respect to healthy people, there is a switch between the face and the brain. And we're still investigating what is happening on the brain, but what we know for sure is what is happening on the face. And by the point is that this is not all the story. So we cannot ascribe to a single gene the evolution of humans. Of course since the neurocruster is doing so many things, you can think that a gene that controls the neurocrust can directly produce a lot of features of phenotypes, but it's not necessarily all the point and we don't believe that. So now we're studying also genes that don't do necessarily only the face or necessarily the neurocrust. We're studying genes that let's say because we know that in the last 400,000 years a lot of mutations we acquired where on genes that are not related to the face are strictly related to the brain synaptic regulations, you all know more or less that neurons work by synaptic activity. I'm simplifying a lot here. We know that the adrenaline which derives from the neurocrust can regulate stress responses. So we know that there is a crosstalk between the brain and the adrenaline, so the neurocrust derived tissues, and the neurons that is important for human behavior, but we know also that the modern face, the slender face, the smaller nose, and so on, appeared more or less 200,000 years ago, while the globular shape of the brain appeared only 40,000 years ago. So it means that a lot of other things happened that we need to clarify and we are trying to study in the lab of course how this happens in our models, but the point is that for instance also writing appeared only 6,000 years ago. So there is a combination of cultural and genetic mutations that happened during human evolution that we need to understand and they are not necessarily neurocrust derived. So the global view is that during evolution there has been a selection for tenderness, a selection for reduced reactive aggression, which is the aggression that you put in place when you react to something that is happening coming from outside. There is a main difference in psychology between reactive and proactive aggressiveness. So proactive aggressiveness is when you decide to do something, you plan to do something aggressive. Reactive aggressiveness is the kind of aggressiveness that happens when you are threatened and it's one of those things that are selected during domestication. This is something that we are sure happened, changed in human evolution. So there is a step of neurocrust selection in which a reduced neurocrust might favor a bigger brain. So there is, we imagine that during evolution we went from wild to modern during different moments of selections that also required some interactions and some gym flow between populations and that's how basically we became humans. An important book that I want to suggest to people interested in the topic is The Goodness Paradox from Richard Wrangham. It's very cool. It starts from the idea that we were selected by being less reactive aggressive, less domesticates and we were more proactive aggressiveness. So we do more planned organized. I think we all know that recently, at least we've seen several times. So a bit like gyms but more complex. So this is all.