Sick of taxes, a lack of rights and living in poverty, French revolutionists condemned Louis XVI to the guillotine on the morning of January 21, 1793. After a short but defiant speech and a menacing drum roll, one of the last kings of France lost his head as a crowd rushed the scaffold to dip handkerchiefs into his blood as mementos.

Or so the story goes.

Lending new life to the demise of Louis XVI, scientists performed a battery of DNA tests on dried blood inside a decorative gunpowder gourd that purportedly contained one such handkerchief. The results, described Oct. 12 in the journal* Forensic Science International: Genetics*, show the blood belongs to a blue-eyed male from that time period: a possible dead-ringer for the executed king.

“The next step is find a descendant either of the king or his mother,” said Davide Pettener, a population geneticist at the University of Bologna in Italy who helped with the analysis. “Otherwise we’ll have to try to get a sample of the dried heart of Louis XVI’s son.”

The son was Louis-Charles, known as the Dauphin (heir to the French throne) or Louis XVII, and he died from illness or poisoning at age 10 more than two years after his father was executed. His heart is kept in a crystal vase in the Cathedral Basilica of St. Denis on the outskirts of Paris.

“It’s going to be very difficult to obtain permission from the French authorities, but we may try,” Pettener said.

An anonymous Italian family who've owned the gourd since at least 1900, possibly the late 1800s, approached one of Pettener's colleagues to do the genetic analysis. Before the family obtained the gourd, it allegedly was a gift to Napoleon Bonaparte, who became First Consul of France in 1799 and Emperor in 1804.

“It’s a very strange story,” Pettener said. “We thought it was a joke at first because we work on population genetics. But we realized it’s very important from a historic point of view.”

The gourd, presently valued at about 500,000 euro ($700,000), is emblazoned with key figures of the French Revolution and bears an inscription that reads, as translated from French into English by the researchers, “Maximilien Bourdaloue on January 21st, dipped his handkerchief in the blood of the king after his beheading.”

There was no handkerchief in the gourd when the scientific team received it, but there was plenty of dried blood inside to scrape out five small samples. Two laboratories performed three kinds of DNA analysis: One probed the Y chromosome (inherited from the father), another scrutinized the HERC2 gene (associated with blue eyes) and the last examined the DNA in mitochondria (the powerhouses of cells, which are inherited from the mother).

The tests showed the blood belonged to a blue-eyed man with a rare genetic makeup and not to an animal, nor to anyone in the laboratories, nor the gourd-owning family nor or any one of tens of thousands of people in genetic databases. Pettener added that the blood is also “quite old,” making a forgery more unlikely.

“A match on the Y chromosome of the Dauphin will immediately authenticate the blood as belonging to the king Louis XVI,” Carles Lalueza-Fox, a biologist at Universitat Pompeu Fabra in Barcelona and lead scientist of the analysis team, wrote in an e-mail to Wired.com. “In any case, even with this information, we have historical evidence that this gourd could in fact contain the blood of the king.”

Images: Paolo Garagnani/Davide Pettener/Elsevier

Citation: Lalueza-Fox, C. et al. “Genetic analysis of the presumptive blood from Louis XVI, king of France.” Forensic Science International: Genetics, Oct. 12, 2010.

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