18th century France, Bastille 14 July 1789, Charlier, DNA, Enlightenment, fluorescently-tagged nucleotides, Forensic Sci. Int. (2012), France, French First Republic 1792, French Independence Day, French motto of liberté égalité fraternité, French Revolution, Genetic comparison of the head of Henri IV and the presumptive blood from Louis XVI (both Kings of France), King Henri IV, King Louis XVI, Marianne symbol of French Republic, Marie Antoinette, Maximilien Bourdaloue, nucleotides, P. Charlier, Paris, Versailles
(English) In 18th century France, King Louis XVI and his posse of French nobles were creating quite a stir. The populace felt that the government was both out of touch with reality and profligate. As the legend is told today, the lower and middle classes were oppressed and feeling progressively more angered by the overwhelmingly rich, pompous, and conservative absolute monarchy and associated aristocrats. The great palace of Versailles is no subtle reminder of financial disparity to the lesser classes, after all. The French Revolution was a time of political, social, financial, ideological, and physical unrest, and the people began to tire of King Louis and his archaic ideas about life, how to rule a country, and his taxes. This indignation manifested in many public protests—peaceful or otherwise. The riots eventually culminated into the taking of the Bastille on 14 July 1789.
The French and many of us Francophiles still celebrate Bastille Day as French Independence Day. Bastille Day is remembered as the point during the French Revolution when the passion of the people and the likelihood of a successful revolution reached a climactic peak. The French First Republic was created soon after in 1792, rendering King Louis’s position as head of state both virtually and nominally redundant. The French were entering the Enlightenment—that era of romanticism that ushered in Western civilization as we know it and commemorated the emergence of the sacred French motto of liberté, égalite, fraternité. The birth of Marianne, the symbol of the Republic, ultimately resulted in the death of good King Louis XVI only one year later, proving that two such antithetical figures certainly cannot exist in the same space. You know where this story ends—at the guillotine, with the decadent heads of Louis and his bride, Marie Antoinette, rolling on the cobblestones. These are historically verifiable events.
The legend element of this story comes by way of Maximilien Bourdaloue, whose name is engraved on a gourd along with an inscription claiming that the gourd contains the handkerchief of Monsieur Bourdaloue, soaked in the blood of King Louis XVI after his beheading. Imagine such a souvenir! This certainly seems like a tall tale, but Charlier and colleagues recently discovered this legend to be true in their publishing of “Genetic comparison of the head of Henri IV and the presumptive blood from Louis XVI (both Kings of France)” in Forensic Science International1.
If you’re not the science type, this may seem like the stuff of Jurassic Park credibility, but DNA extraction and comparison is actually not super complex—certainly less complex than rocket science, at least. The biggest obstacle of working with such aged samples is that the DNA is likely to be compromised from decay, making the sample quite small. Therefore, the first thing to do is make a lot more DNA.
Making more DNA is possible through the polymerase chain reaction (PCR). PCR takes DNA that has been extracted from a real, live organism and amplifies the sample by creating many, many more copies. This is a Nobel Prize-winning reaction that allows million-fold amplification of a very small amount of DNA, possible because of a unique protein that can function under the extreme heat conditions necessary for PCR. In the experiment summarized by Charlier, the formerly real, live organism is the purported blood of King Louis XVI from the interior of the legendary gourd.
Several components go into the solution of PCR, but it is important to note here that it is absolutely necessary to include nucleotides and fluorescently-tagged nucleotides. Nucleotides are the building blocks of the DNA of every living thing on this planet. There are four different nucleotide identities, each with a slightly different structure. It is the sequence of these nucleotides in our DNA that provides the information necessary for our bodies to sustain life.
Anyway, here’s how PCR goes: Denature. Anneal. Elongate. Repeat. See? Simple. Denaturing tears the two strands in the double helix of DNA apart. Annealing attaches new nucleotides, one by one, to the both original, single strands of DNA, forming two helices where before there was one. Repeating this process yields literally millions of copies of a single DNA helix. However, when the fluorescently-tagged nucleotides are incorporated into a strand, strand growth stops. This leaves a mixture of many DNA strands of many different lengths. In theory, strands of every possible length should result.
Now that we have enough sample to analyze, what do we do with it? Sequence it. Much of the DNA in any given individual can have the same sequence, so the areas we’re interested in are called hypervariables. These are most likely to differ from person to person and provide the most compelling evidence that the DNA in the sample belongs to our dead king. In the case of our friend Louis, the sequence of hypervariable region 1 of his mitochondrial DNA was compared with a putative sample of King Henri IV, an historically known relative.
The method referenced in Charlier’s study for sequencing DNA is called capillary electrophoresis. This process separates DNA strands by electrically moving the sample through a gel sieve, which filters DNA strands by length. The strands are then evaluated by a machine, in this case, the Genetic Analyzer from Applied Biosystems, which detects the fluorescent tags at the end of each strand. The fluorescent tags are unique to each nucleotide identity, and the Analyzer can recognize which tags are associated with each nucleotide identity. The Analyzer finally spits out a spectrum to be evaluated by the researcher with colored peaks, each peak indicating, in order, the identity of each nucleotide in the sequence.
By doing this, Charlier et al. discovered three rare mutations in King Louis’s mitochondrial DNA. These mutations were discovered in only one person in a database of 22,807 Europeans. This evidence, along with a Y-chromosome profile comparison to Henri IV, strongly suggests that the DNA in the gourd did indeed belong to King Louis XVI.
It is incredible that modern technology can offer insight into such obscure and dated anecdotes that turn out to be realities. Narcissistic King Louis would probably be intrigued and excited that he is the topic of scientific buzz in the 21st century. Unfortunately for him, it’s not enough to overshadow his reputation as the last King of France; but for us Francophiles, it is a stimulating morsel of French history that seems just a little more tangible as it occurs right before our eyes. While King Louis XVI did not reign long, he lives on in the fascination of students of French and history. Long live the king.
1. P. Charlier, et al., “Genetic comparison of the head of Henri IV and the presumptive blood from Louis XVI (both Kings of France),” Forensic Sci. Int. (2012), http://dx.doi.org/10.1016/j.forsciint.2012.11.018
Andrea Johnson received her B.S. in Biochemistry with a minor in French from the University of Minnesota in May 2012. One semester of her degree was spent abroad in France where she cultivated her love of French language, food, wine, and navigating interactions with others from foreign countries. She currently lives in Minneapolis and works as a contract employee through Pace Analytical Services at 3M in Maplewood, MN. She spends one evening each week volunteering at the Emergency Department at Amplatz Children’s Hospital in Minneapolis. While she enjoys living in her home state, she is impatient to be abroad again, since travel is her joie de vivre.
You may also enjoy A Woman’s Paris® post, French Crown Jewels: Empress Eugénie and French Empress Eugénie and her diamonds, by Barbara Redmond who writes about pieces from Empress Eugénie’s private collection and the French Crown Jewels that were split up by the national assembly and sold at public auction. Stories of Empress Eugénie’s famous Bow Brooch, Pearl and Diamond Tiara, and private jewels. Including Barbara’s favorite book about the jewels in the Louvre, Paris.
Bastille Day in France: la fête nationale, by Canadian writer Philippa Campsie who says, if you are going to be in France this coming Bastille Day (usually known as le quatorze juillet or la fête nationale in France), you might want to learn the words to La Marseillaise, which has been France’s national anthem (off and on) since the days of the Revolution. Including words to the anthem in French with English translation.
Marianne: National emblem of France, by Canadian writer Philippa Campsie who tells about Marianne, the feminine symbol of liberty and republicanism in France. Originally, images of Marianne were created using anonymous models, but modern depictions have featured famous French beauties, such as Brigitte Bardot, Mireille Mathieu, Catherine Deneuve, fashion designer Inès de la Fressange, among others.
Tom Hooper’s “Les Miserables,” is big, breathtaking… bland? Film critic David Lundin gives us a view, behind the scenes, of the making of this 2012 Hollywood movi-musical, Les Miserables, based on Victor Hugo’s novel of the same name published in 1862. Les Miserables is an operatic tale of a man’s struggle to find peace against the backdrop of a growing people’s revolution and weaves the stories of a dozen or so primary and secondary characters. (French)
Text copyright ©2013 Andrea Johnson. All rights reserved.
Illustration copyright ©2012 Barbara Redmond. All rights reserved.