Video: The biomolecular tales of our ancestors | Alisa Kazarina

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Translator: Ilze Garda Reviewer: Rhonda Jacobs Imagine a parallel universe that coexists in the same place as our universe, in the same space, at the same time. This universe is overcrowded with life forms.

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It is invisible and intangible like the finest layer of reality, which we cannot notice. But it is there, and it maintains the functionality of our everyday world. Without it, we just wouldn't exist. Now, would you be surprised if I told you that actually everything I said before is true? Because I'm about to tell you this. I'm talking about the world of microbes -

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a separate world, yet so deeply connected to us. And the story of this connection expands far away into the past. But thanks to modern science, we are now able to read this story like a history book. Ladies and gentlemen, I proudly present biomolecular archeology, the science behind this history book.

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And I am here to share with you what fascinating things we can try to manage with this powerful modern science. But let's start with the term itself: biomolecular archeology. It's not even easy to pronounce, not to mention to try to understand the essence of this phrase. There might not be a problem with the archeology part, right? We've all seen it in movies, we know what it is about,

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but what is "biomolecular" anyway? The first thing that comes to mind: it is something about biology and molecules. And this is actually correct. A biological molecule, or a biomolecule, is any molecule that is present in a living organism. Now, there are all sorts of molecules in your body, but undoubtedly, the most informative one is DNA.

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So, let's bring it back together. Biomolecular archeology enables us to study the DNA recovered from archeological samples. And not only native human DNA, which, of course, all by itself gives lots of study perspectives, but also the DNA of microbes that lived side by side with that human. This science is relatively young.

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About ten years ago, a massive breakthrough happened in genomic research technology. A method appeared which is called NGS, next generation sequencing, and this method significantly cuts time and costs of any genomic research. For example, have you ever heard about the Human Genome Project? It was quite a popular topic for science fiction some time ago.

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This project launched in 1990 with the goal to decrypt all genomic information in a human organism. At that time, with the technology of the time, it took ten years and three billion dollars to reach the goals of this project. With NGS, all of that can be done in just one day at the cost of 15,000 dollars. On the fertile soil of next generation sequencing

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arose biomolecular archeology because there is a great lot of genomic information to be analyzed and it just wouldn't be possible to manage such research with olden day technology. Now we are able to manage such research OK, "But why?" you could ask me. "What benefits can we get out of this information?

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What can we use it for?" The answer appears to be quite wide. Consider human health as a complex and dynamic system. Apart from genetically determined factors that are stored in our DNA, our health is severely influenced by many other factors, like our lifestyle, our diet, and our fellow microbes.

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One hundred trillion cells, one and 14 zeros, that's the approximate number of microorganisms in your body, ten times greater than the number of your own cells. Your microbial baggage occupies almost 2% of your body weight, that's about one and a half kilograms, approximately the weight of your liver. Or your brain.

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And all these are microbes. Just think about it for a second! Human microbiome, that's the modern term for all microbial communities inhabiting your body, has earned a close attention over the last decade. It seems that we are only beginning to discover the mysterious role that is given to microbes in the performance of our health. In 2007, the National Institutes of Health of the U.S.

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launched the Human Microbiome Project to finally study its relation to our health conditions. And since then, it has only become clearer that our notion about our fellow microbes is inexcusably poor. Francis Collins, the director of the National Institutes of Health, even compared the researchers involved in the project with the 15th century explorers

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discovering the outline of a new continent. It is now being suggested that a range of modern, widespread diseases, starting from obesity, Crohn's disease, other gastrointestinal problems to all sorts of allergies, autoimmune diseases, or maybe even cancer, may appear to be consequences of microbiome changes. But where do these changes come from?

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When did they first appear? What was the triggering factor? These are the questions we are trying to find answers to at the moment. This topic always triggers a memory of my first conscious experience with the microbial world around. My mother, like any attentive parent, tried her best to warn me against the invisible dangers of the world, and she told me a story

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that every time I do not wash hands before eating something, I become a reason of global microbial migration. (Laughter) An uncountable number of microbial families come together, pack their suitcases, their TVs, their favorite toys, and leave their houses forever to move to a new area which is thought to be my body.

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Now, I was a child with a very vivid imagination, and this story influenced me so much that I was obsessed with handwashing for a really long time. It actually took me years to overcome the thought that I'm doing something wrong when I initiate this microbial migration, and to understand finally that they are actually willing to come, they've got friends there waiting for them.

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I'm not trying to convince you not to ever wash your hands again, of course not. But let's try to be moderate with it. We lack this microbial diversity nowadays. And as we know from ecology, the most diverse systems are the most stable ones. This might be one of the reasons for our so-called diseases of civilization.

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And this is exactly the type of hypothesis for biomolecular archeology to deal with. It turns out that there is a unique archaeological material that so preciously stores the enormous amount of information related to ancient human microbiome, and this material is ancient dental plaque, thanks to the fact that oral cavity hygiene was not on the list of top priorities for humans of the past.

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Their oral microbiome has already been partly fossilized during their lifetime in the form of dental calculus, which, in turn, stays in soil as well preserved as the skeletons themselves. Sadly, we can't help these fellas anymore. But they can help us by providing unique and precious information about their microbes and their health,

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and maybe we will have a chance to help others in the future thanks to them. There is one more vast human health-related aspect where biomolecular archaeology takes its rightful place, and this field of research expands into the valley of ancient deadly pathogens. It is true that the vast majority of microbes either provide us some kind of benefit

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or do not really care whether there is a human around. But there are some ancient deadly microbes that still remain an urgent problem nowadays all around the world. For example, Mycobacterium tuberculosis. One and a half million deaths in 2014. And OK, OK, I know, the first reaction I always get is like, "Wait, aren't there antibiotics?"

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or "I heard there is even a vaccine; is this disease still dangerous to us after all?" The answer is yes; tuberculosis is closer than you think. Because of some mysterious genetic phenomenon, there are people that can carry around this microbe their entire lives without developing any symptoms, and there are people that develop symptoms straight ahead after infection.

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Let me give you a real example of a tuberculosis microepidemic. Let's say a person somehow got infected. He works as a teacher in a junior school. Half a year later, one of his pupils develops symptoms. A few months later, the older sister of the pupil. A few more months later, two friends of the sister. This is how it spreads. When I was just starting my research on this topic,

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I myself was very surprised to know that tuberculosis worldwide remains one of the major health concerns, that on the list of infectious diseases, it is the second most common death cause after HIV. Yes, the fight continues. Did you know we have a tuberculosis clinic right here in Latvia, just outside Riga, where many doctors and other specialists fight tuberculosis on a daily basis?

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To finally beat this harmful bacteria, it is crucial to understand how it evolved, how it developed resistance to antibiotics, how it spread. And these are the questions where biomolecular archaeology can help us a lot. At the moment, working in the Latvian Biomedical Research and Study Centre, we have managed to identify Mycobacterium tuberculosis in one archaeological sample from the 17th century.

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We are now in the process of defining its whole genome, so we can understand what type of tuberculosis reigned at that time over the Latvian territories and where it came from. Obviously, biomolecular archaeology impacts humanities as well, such as history and anthropology. These, for example, are the excavations on the Saint Ģertrūdes Cemetery a few years ago.

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They started very spontaneously. There was an idea to build a shopping center in that area, and there was also information that there might be some medieval burial sites. So the Latvian Institute of History received a request to check it out. And they did actually find a medieval burial site, quite a massive one. Our archaeologists dug out over 500 skeletons,

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and found 2,000 more skeletons buried separately in a giant wooden box. But what was it? This couldn't be war because the skeletons lacked war lesions on their bones. Was it hunger? Epidemic? Archaeology itself cannot take this research any further, we have to intervene with biomolecular methods. Only then can we trace the true reason.

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The research process that implements the goals of the science is fascinating, even by itself. It all starts with ancient bones and teeth from cemeteries all around Latvia. We then cut out small pieces of these bones and shred them in special scientific mills to get bone powder. We then extract all the DNA that is captured in a specific bone powder sample,

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and then we sequence it. Sequencing is the process where the machine reads the DNA code and translates it into a four-letter code. By the way, it is absolutely fascinating how all genetic information of human beings and all other living creatures on the planet Earth can be written down using the alphabet containing four letters only. It's absolutely not surprising that the result of the sequencing is absolutely unreadable -

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gigabytes of text consisting of these four letters. It then takes time and effort to analyze these data with a variety of computational methods and programming approaches. And at the very end, we get a pretty readable list of all the microorganisms from a specific sample. The field of my research contains three sciences at once: archaeology, biology and computer science, all mixed, merged and connected.

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It's like the science itself merging and connecting humanity throughout centuries. Science is like a pyramid: you cannot lay the upper block without a foundation of the blocks beneath. And building this pyramid of healthcare throughout the entire human civilization, I believe biomolecular archaeology just opened up a new frontier for us. Where do we go from here?

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It's a question of choice, but I believe that any destination holds fascinating discoveries. But just for now, please remember that you are never alone. (Laughter) You've got a hundred trillion friends that are always there for you. Think about it next time you want to wash your hands. Thank you. (Applause)