It’s been a hot minute since we’ve talked about incestuous royalty from the middle ages, so.
Today’s Moment of Science… the Habsburg Chin.
History has provided occasional hints that all of Rudy Giuliani’s decisions are bad, but let’s delve into the science behind why you shouldn’t bang your cousins. Most of us are blissfully unaware of the extent of our chromosomal fuckery because it only dropped into our genetic code from one parent. Even when both parents are carriers of a recessive gene, there’s only a one in four chance of genetic shenanigans from both passing it on.
Contrary to what we may imagine, it doesn’t require Biblical level inbreeding to sneak a few super annoying alleles into circulation. The smaller the population though, the higher your chances of winning whatever the opposite is of the genetic lottery.
One famous case of inbreeding, the smurfy quirk of the Fugate family, didn’t actually begin as a result of inbreeding. Martin Fugate moved from France to Kentucky in the early 1800s, met Elizabeth Smith, and these caucasion lovebirds popped out a bunch of blue babies. They just happened to both have a rare recessive gene for a goddamn ridiculously rare condition called methemoglobinemia. Possibly to avoid ridicule from the outside world but also because there were only a handful of families nearby, they intermarried with such a small group that a lot more blue people popped up in the area. In an interview, a descendant of the Fugates pointed to the family tree and said “I’m kin to myself.”
There’s medication to treat the condition now. And to prevent it, there’s always marrying someone you didn’t meet at a family reunion.
But throughout Europe in the Middle Ages, several powerful families’ preferred method for consolidating power was to arrange marriages specifically for something called ‘limpieza de sangre.’
Which is the fanciest possible way to say ‘the royals were a bunch of cousin fuckers.’
This almost certainly contributed to history’s most famous case of mandibular prognathism (MP), aka the royal underbite, aka the Habsburg chin. The TLDR version goes that when they came to power in Spain in the early 1500s, efforts to keep the bloodlines pure coaxed a mild underbite into a jaw of legend. By the time Charles II showed up, he had all the genetic diversity of a French bulldog.
In the absence of DNA samples, the Habsburg dynasty that birthed rulers of half a dozen European countries left plenty of documentation behind to parse through what happened. When all the marriages, births, and deaths from the era are mapped out, studies have shown an increase in infant and childhood mortality during the sixteenth and seventeenth centuries, which is not unexpected with inbreeding. An alarming number of the marriages were first or second cousins, uncle and niece, or had enough genetic similarities circulating from previous generations of intermarriages that they were about as related as first cousins.
Another record the Habsburgs left behind were their portraits. A group of maxillofacial surgeons examined multiple paintings of fifteen members of the family, analyzing for specific features of MP along with maxillary deficiency (MD), in which the bones of the upper-jaw are under-developed. It seems the famed chin is a combination of MD and MP, both of which were amplified over the years of whittling the family tree down to a stump.
Charles II of Spain, who was as inbred as if his parents were siblings, had amongst the highest visible degree of facial deformities. He reportedly had other physical and mental disabilities, but it’s hard to know what’s from inbreeding, what’s from plain old bad luck, and what’s historical myth. His autopsy reported that his heart was “the size of a peppercorn, his lungs corroded; his intestines rotten and gangrenous; he had a single testicle, black as coal, and his head was full of water.” Which is hard to reconcile as truly the condition of his body during life, given that he was reportedly physically active and participated in diplomatic work.
He became king at just three years old, and while it’s doubtful he would have been remembered as a great ruler even in the best of times, he was dropped diaper-first atop an empire in decline. I’m doubtful that some of the color commentary isn’t just shit talking the last Habsburg who sat on the Spanish throne.
His sister, Margaret Theresa of Spain, had similar facial features but none of the rumors followed her through history. She married Holy Roman Emperor Leopold I, her uncle on one side and her cousin on the other because jesus fucking christ this family. Three out of four of her children died in infancy, which she blamed on the Jews instead of all the goddamn inbreeding, for which she had her husband expel the Jews from Vienna.
Maria Antonia was her one child who survived infancy. More inbred than Charles II had been, she was remembered as “intelligent and cultivated.”
This has been your Moment of Science, reminding you that royalty still hasn’t entirely shaken this habit.
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