Scientists hunting for the DNA of famed Renaissance artist and scientist Leonardo da Vinci say they’ve made a breakthrough—but some experts caution against interpreting the results as a smoking gun.
As first reported by Science on Tuesday, researchers at the Leonardo da Vinci DNA Project, housed at the J. Craig Venter Institute in Rockville, Md., reported that they traced male DNA in samples taken from Holy Child, a chalk drawing attributed by some to Leonardo, as well as other artifacts. The findings are detailed in a preliminary paper posted on the preprint server bioRxiv, and they are yet to be peer-reviewed.
Leonardo’s genome is an elusive target. His remains couldn’t be verified after they were disturbed during the French Revolution. Many of his direct relatives’ remains are still being investigated, and he had no known children. All of that makes identifying his DNA extremely difficult, if not impossible, says David Caramelli, an anthropologist and ancient DNA specialist at the University of Florence in Italy, who is a member of the Leonardo da Vinci DNA Project but was not involved in the new study.
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To try and get around these limitations, Norberto Gonzalez-Juarbe, an assistant professor of cell biology and molecular genetics at the University of Maryland, and his colleagues at the project analyzed several samples taken from various artifacts. They found traces of plants and other environmental signatures that lined up with times and places in the polymath’s life, as well as male DNA with a Tuscan lineage that could, they speculate, point to Leonardo himself.
Manuel Porcar Miralles, an applied microbiologist at the University of Valencia in Spain, who was not involved in the work, says it is “spectacular” and appears to be “technically robust.”
The effort is somewhat comparable to solving a modern serial killer mystery by looking for the same DNA across different crime scenes, says John Hawks, an anthropologist and a professor at the University of Wisconsin–Madison, who was also not involved in the study.
“If you can find the same DNA pattern on paintings, drawings or even places connected with Leonardo,” he says, “you would have some confidence you are looking at his genome—even without being able to find genealogical relatives today.”
Still, the reality is more complicated: Leonardo’s artwork has been covered with the DNA of an unknown number of people—from contemporaries of the man himself to art handlers working in museums today—presenting a clear challenge to researchers.
“I think the work has not quite gotten there yet,” Hawks says.
Porcar Miralles, who is also CTO of Darwin Bioprospecting Excellence, a microbiology start-up, agrees: tracing the male DNA to Tuscany doesn’t guarantee it belonged to Leonardo. It is entirely possible the DNA belonged to any one of the “dozens or even hundreds of people from the region who may have touched the artworks once if was completed,” including after the painter passed away, he says.
For Hawks, that may not be such a bad thing. The information gleaned in the analysis still helps to paint a picture of Leonardo’s environment and his community.
“What’s compelling is that every artwork and object from history may have trace DNA, all adding up to a picture of the network of people connected with these objects,” Hawks says.
The study authors attempted to flesh out some of those stories: traces of citrus found in some of the samples might connect to the gardens of the powerful Medici family, which ran Florence for hundreds of years and employed Leonardo.
But while that’s a compelling story, the researchers failed to authenticate the age of the DNA, a significant limitation of the study, Caramelli says.
Indeed, Gonzalez-Juarbe admits that the researchers were limited by the small size and piecemeal nature of their dataset, as well as by how little DNA they were able to extract from each sample. Still, he says, the methods laid out in the paper may serve as a baseline for future research.
The results could become “more robust,” Porcar Miralles says, if the researchers can find confirmed remnants of Leonardo or if they can collect DNA from any of his living relatives that matches the samples they found.
“I hope we are able to test multiple cultural artifacts from the [Leonardo da Vinci] lineage and combine our findings with those of living descendants,” Gonzalez-Juarbe says.