Kendra Pierre-Louis: For Scientific AmericanIt is Science quicklymy name is Kendra Pierre-Louis, I’m replacing Rachel Feltman.
It has been more than 500 years since Leonardo da Vinci died. Yet over the centuries that followed, interest in the Italian mathematician, who seemed to move with ease between art, architecture and engineering, among other fields, only grew. The same goes for its DNA.
About ten years ago, researchers from a wide variety of disciplines, ranging from forensics to genetics to art history, came together with the aim of discovering the DNA of the Renaissance artist. Da Vinci had no children and his remains were disturbed during the French Revolution. The hope is that the discovery of his DNA could open the door to a number of discoveries, including new tools for authenticating works of art and potential clues to Leonardo’s strange way of seeing the world.
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Now, a new preprint (meaning it hasn’t been peer-reviewed yet) reveals that the team found male DNA in a chalk drawing called Holy Child this is often attributed to the master. Researchers say it’s possible the genetic evidence came from Leonardo da Vinci himself, although not all researchers agree.
To learn more about this article and the project as a whole, we spoke with forensic legend Rhonda Roby. In addition to being part of the Leonardo da Vinci DNA Project, Rhonda is known for her work using DNA analysis to identify the remains of people killed during 9/11 and Pinochet’s 1973 Chilean coup. She was also part of the team that identified the remains of Tsar Nicholas II, alongside other members of the Romanov family.
Thank you for taking the time to chat with us today. Can you tell us a little about the Leonardo da Vinci DNA project, how it started and above all what was your role within the team?
Rhonda Roby: Yes, this team is fascinating and I am just a small member of a very large team. So there are experts in Leonardo’s art, art historians. There are geneticists and environmental specialists. There are doctors. And everyone brings a lot of their knowledge to this information that we’re trying to gather, which is: what can we learn about Leonardo? What can we learn about his ability to see things that you and I simply don’t have that ability to see? He could see the flapping of a dragonfly’s wings, but you and I don’t have that ability. What gave him the ability to see and imagine helicopters [Laughs] when there weren’t even helicopters built, right? So I think there’s just a great team of people in the world in general [who] are interested in Leonardo and the genius of this man.
So I was a professor at the J. Craig Venter Institute in La Jolla, California, when I was approached for this project. And we actually published a piece in 2021, so this has been going on for a long time, obviously – where we went to a private collection in someone’s home, and we sampled and tested artwork from their private collection at that time.
And so I was always involved with the people on the project. I worked on some of the history of the family tree and Leonardo’s current relatives. And so I just… I had the chance to be part of the team, to bring some of my expertise as a forensic pathologist. You should know that we often work with very small samples. The researcher often works with blood samples. You know, someone who’s looking…
Pierre-Louis: Yeah.
Roby: For the cancer gene, they take an entire tube of blood from someone and, you know, they have a lot of material to work with, whereas in this example we’re looking at works of art that are Leonardos, are potentially Leonardos that have very, very small biomass associated with them. And so that’s the most exciting part for me.
Pierre-Louis: And just to make it clear, what you’re essentially doing is: you have this huge team of people coming together to try to find any potential fragments of Leonardo’s DNA and try to put it together to get a picture or an idea of what his DNA might have looked like because you don’t have his DNA.
Roby: RIGHT. We don’t have that, do we? And no identified material belongs to him. So if you could bring this team of people together and look at different approaches and, you know, look at a piece of history here and understand it a little bit, that would be great.
Pierre-Louis: And from what I understand recently, part of the swabbing project, one of the things that you were able to specifically swab was the Holy Child, which is a chalk drawing believed to have been drawn by Leonardo da Vinci. First of all, how did this sampling of this work of art happen, and also, what did you learn from this sampling?
Roby: Several things we learned and one of the first things we did was from Dr. [Thomas] Huber, who is in our group, made a really nice picture of it, and what we were able to do was we were able to manipulate that picture and move it around and look at it from all the different perspectives, so we weren’t manipulating the actual – potential – Leonardo drawing, right? So we had a piece of paper that we could move. We could look into it. We could look into it. We could discuss, “Well, what do you think of the sampling here? What do you think of looking at it here?” I thought it was a brilliant idea.
The second thing I learned from working with Dr. [Thomas] Sakmar and Karina Äberg – she is an artist – and the way people handle works of art. Sometimes they manipulate the artwork into the corners, and that makes a lot of sense to me, right? You’re not going to handle a work of art in the middle…
Pierre-Louis: Yeah.
Roby: Where the main objective is. So we focused a lot of our work on the corners of the artwork areas, thinking that someone could manipulate that area very, very closely. So it’s fascinating, right? As a forensic scientist, a geneticist, I’m going to dig in the middle of a bloodstain to get my evidence, right? [Laughs.]
Pierre-Louis: [Laughs.]
Roby: But here we’re sort of looking at the periphery.
Pierre-Louis: It feels like with the techniques you use, it’s almost like a mystery or a puzzle that you’re trying to put together without actually being able to see the picture on the puzzle box. Is this what you feel?
Roby: I mean, it’s definitely a headache. I never thought of it that way, but maybe that’s science: it’s a puzzle without knowing exactly what you’re looking at, yeah. Yes, so we’re trying to make discoveries, and the goal of those discoveries hasn’t always been just to find Leonardo’s DNA but to understand, you know, how this drawing or this painting has evolved throughout history because it has historical significance, something that’s 500 years old.
Pierre-Louis: I know that often with big, bold, ambitious projects like this, people focus a lot on whether or not you succeed, right? The focus is often on, you know, “Do you have the DNA yet?” or other. But one of the questions I have for you is: what kind of progress have you made along the way? I’m wondering if there’s something that, you know, over the decade or so you’ve been working on this project where you’ve managed to advance the science or the techniques in interesting ways that maybe don’t get as much attention as you’d like.
Roby: Yeah, so one aspect of it is that, you know, we looked at different sampling techniques, right? And we took liberties with some lesser known works of art and made holes in them, drilled holes through them…
Pierre-Louis: [Laughs.] Oh, wow.
Roby: And so, but we did that to try to figure out: what is the hardware that we’re going to get? We did a 1.2 millimeter punch, a 2 millimeter punch, you know, and so on. And what information will we obtain? Most likely, the stronger the punch, the more material you’ll get, right? So it’s about testing those hypotheses and figuring out what insights you can glean from them.
So we don’t want to damage any artwork, so that’s always been at the forefront. But what can we do? How lightly can we dab and how hard should we dab to remove the material? So I think we learned something there. We even used a wet vacuum system, where we wet the material, then vacuumed the pads and collected the materials.
And then I think the other area that, you know, we’ve learned a lot about – and this is just decades and decades of work in genome science – is just the accumulation of data, the whole genome sequencing that’s happening, the compilation of that data and the extraction of information from that data, and the bioinformaticians who are working in that area and extracting information. It’s fascinating too.
Pierre-Louis: I think a lot of people think, “I don’t know if you need a lot of DNA.” [Laughs]”to get something”, but it seems like you are working with very small samples.
Roby: Yes, that’s right, these are very small samples, aren’t they? And I was looking at art around my house, and I have a framed photo right in front of me that’s been there for probably 20 years and hasn’t moved, right?
Pierre-Louis: Yeah.
Roby: And I’m sure it’s been dusted and everything else, but it might give you some information – not just human DNA but, you know, microbial DNA, things that happened in that house, in that room. You might learn a little more about this by getting the very small sample size you get from this.
There’s one thing I want to make sure I’m clear about: Everything you have, everything you touch, we can extract some kind of DNA from it – anything that has been exposed to the environment. So you are absolutely right: these are small amounts. The researcher looking for the cancer gene doesn’t want a small sample, right, but a forensic pathologist often works with a small sample. And then we know that we’re starting with very low biomass, we know that we’re starting with very small materials, and we know that these materials are not just human. We know there’s going to be bacteria or, you know, fungi or viruses, mixed in with that.
Pierre-Louis: I think that in one of the articles I read, on one of your samples Hey, have you found malaria?
Roby: Yes, and that comes from some of the letters that were sampled.
Pierre-Louis: It’s wild.
Roby: It’s fascinating, it’s interesting, isn’t it?
Pierre-Louis: Yeah.
Roby: I mean, and you stop and think about that for a minute, right? It’s not a living organism that will be transmissible, but there is historical evidence that it was there at one time.
Pierre-Louis: I know that as researchers you don’t necessarily think about practical applications, but one of the possible use cases I’ve seen for the techniques you use is potentially the ability to authenticate other works of art. So once this project is completed, people will be able to use this technique to… instead of relying on, you know, paintbrushes or, like, other things. [Laughs]other elements that historians have used to determine whether or not a specific artist created a work. I was wondering if you could talk a little about that.
Roby: Yeah, so I know that’s a goal of people, is to be able to give that kind of information. And I think we need to collect a lot more data. I think there needs to be a lot more access to artwork, historical documents, etc. so that you can create a database of all kinds of information that you can take from it to be able to say something about provenance in the future.
So let’s say you had a work of art that you could say was by a certain master artist, and then you had a second one, and then a third, and a fourth, and you knew that all of those belonged to that master artist. And then you’ve worked on this biome, and you’ve developed some kind of database, and you see a pattern with those – so maybe that could lead to, [in] the future, less known, which you could compare to this database.
But I think that — it’s in the future. We’ve taken some first steps, and I hope people can go ahead and look at some of the techniques, some of the successes that we’ve had here, and build on those and be even more successful in being more confident about where something comes from, right?
And then I think, just like in a criminal case that we’re doing, there’s a lot of information that’s gathered, right? So if you’re talking about my job, I mean, there’s fingerprints, there’s eyewitness testimony, there’s alibis, and then there’s DNA testing and maybe digital evidence and all that, right? It’s a deal. It’s… you take all of this information together to build on this case. I think it’s the same thing here, it’s a piece, an exciting piece, and I think we can build on it.
Pierre-Louis: That makes sense. It’s like when we first learned how to do radiocarbon dating, and, you know, you can – now that we have it, you can use it on a fake – or, or on a painting and, like, just based on age, be able to say, like, “Oh, well, that can’t be real.”
Roby: Absolutely, but when they first did it, it’s true…
Pierre-Louis: RIGHT.
Roby: When they first did it, they were like, “Ooh, does this work?” And then they had to get more and more data. Nice example.
Pierre-Louis: That makes sense. I have a pretty serious question for you, which you alluded to up top, when you were talking about hope, if you get more of Leonardo da Vinci’s DNA or if you’re able to sequence his DNA, to be able to use his biology to, for example, see if something like his visual acuity might be partly rooted in his genes, right? For example, genes never tell the whole story; you and I both know they’re telling part of the story. But we kind of live in an age of white supremacy and tech billionaires who are trying to genetically modify children and are eager to find their intelligence in their genes. And I wonder if there are any [concerns]that you fear that work like this could be weaponized to support such goals.
Roby: Yes, so there’s a whole discipline of people working in these areas. This is a difficult question to answer. Do I, do I worry about this? No, not because of the work I do. I’m just a scientist trying to answer a few questions, right?
And you know, I hope that people will use science to help us in this world. And obviously there are people, very intelligent people, who sometimes use science to make dirty bombs and stuff. So yeah, I can’t spend my time worrying about what people will do with the little information I put out there, because if I did, would it hinder the work that I’m doing – just to learn things, to be well informed? So I’m not worried about that and I hope it doesn’t seem irresponsible.
I read something that someone wrote about the work that we’d been doing, and he said, you know, “This will give us a foundation that we can build on and learn more from.” » And that’s what I hope it’s about.
Pierre-Louis: Thank you so much. It’s been delicious and I think the passion you have for it has really come through.
Roby: Oh, thank you, Kendra.
Pierre-Louis: That’s all for today. Tune in Monday for our weekly news roundup.
But before we go, we’d like to ask for your help with an upcoming episode: it’s about kisses. Tell us about your most memorable kiss. What made him special? How did you feel? Record a voice memo on your phone or computer and send it to ScienceQuickly@sciam.com. Be sure to include your name and where you are from.
Science quickly is produced by me, Kendra Pierre-Louis, with Fonda Mwangi, Sushmita Pathak and Jeff DelViscio. This episode was edited by Alex Sugiura. Shayna Posses and Aaron Shattuck check in on our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more recent and in-depth scientific news.
For Scientific American, This is Kendra Pierre-Louis. Have a great weekend!