Researchers led by Serena Tucci at Yale University used ancient DNA to identify malaria parasites in the remains of Francesco I de' Medici and Giovanni de' Medici. The study, published in iScience and publicized on June 30, offers new evidence about Francesco I de' Medici's 1587 death.
Working with paleopathologists from the University of Pisa, the team analyzed DNA extracted from the ribs of both brothers. They found genetic traces of Plasmodium falciparum in Giovanni de' Medici and molecular traces of P. falciparum and P. malariae in Francesco de' Medici.
Francesco I de' Medici ribs
Francesco I de' Medici, the Grand Duke of Tuscany, and Bianca Cappello died a day apart after falling ill with intermittent fevers following a stay at a mosquito-filled villa. For years, their deaths were tied to rumors that Cardinal Ferdinando de Medici had them poisoned with arsenic, but the new DNA evidence points in a different direction.
Giovanni de' Medici died of malaria 25 years earlier, and researchers said the genetic match in his remains helped anchor the interpretation of Francesco I de' Medici's bones. It was the first time the brothers' skeletal remains were genetically analyzed.
University of Pisa analysis
Serena Tucci led the research team that examined the ancient DNA in the rib samples. Yale University researchers said in the press release: "Using historical specimens can not only help us understand our past better, but also it can help build a better future."
Malaria was endemic to central Italy during the Renaissance, which makes the parasite findings a plausible explanation for the illness that preceded the deaths. The study does not lay out every step of the DNA identification in the bones, but it does provide direct genetic evidence from both brothers rather than relying on the old poisoning rumors alone.
June 30 press release
The June 30 press release moved the research into public view after publication in iScience. The finding now leaves Francesco I de' Medici's death tied to parasite DNA in the remains, not to the arsenic theory that circulated for generations.
