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King Charles II of Spain, was the last Habsburg ruler of the Spanish Empire. He is now best remembered for his physical disabilities. Source: TRAJAN 117 / Public Domain

Inbreeding Armageddon Annihilated The Habsburg Dynasty

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Scientists have proven inbreeding brought about severe facial deformations and collapsed of one of Europe’s most powerful historical dynasties .

The royal European Habsburg family sat on the throne of the Holy Roman Empire from 1438–1740 AD and scientists have now proven that while carefully arranged intermarriage helped build their vast empire, it also led to their extinction.

Inbreeding Linked With Severe Facial Deformations

Having analyzed the levels of facial deformity in 66 portraits of 15 members of the Habsburg family, lead researcher and geneticist, Roman Vilas of the University of Santiago de Compostela, published his findings in the journal  Annals of Human Biology . “Habsburg jaw”, according to the team of researchers, was a prominent facial deformity that affected the European royal family after 200 years of inbreeding and until this study it hadn’t been clear whether the family's characteristic jawline had been the result of inbreeding or not.

After 10 teams of geneticists and surgeons studied the deformities observed in 11 of the family portraits and then compared the portraits with known inbreeding patterns across the family tree , it was established that there was indeed a link between inbreeding and the propensity of observed facial deformations.

Habsburg family picture, shown Philip IV of Spain, Margaret Theresa of Spain, Diego Velázquez, and Mariana of Austria. (Dcoetzee / Public Domain)

Habsburg family picture, shown Philip IV of Spain, Margaret Theresa of Spain, Diego Velázquez, and Mariana of Austria. (Dcoetzee / Public Domain )

Inbreeding Armageddon Of The Habsburgs

A 2016 Ancient Origins article explains that this mega-rich and influential European dynasty created a “hermetic reality” involving only those with Habsburg royal blood , and while from outside their empire everything appeared perfectly fine, their history contains many shameful and weird episodes leading up to Charles II of Spain in 1740, who being incapable of producing an heir brought the ancient family's senior branch, the male line lineage, to an end. And it completely collapsed when Charles VI daughter, Maria Theresa von Osterreich , died in 1780.

The University of Santiago de Compostela researchers have shown for the first time, “a clear positive relationship between inbreeding and the appearance of the Habsburg jaw”, which Professor Vilas and colleagues achieved by analyzing what are known as the “11 features of the Habsburg jaw”, a condition known in medical circles as 'mandibular prognathism’. Further to this, the teams were tasked with analyzing seven features of so-called ‘maxillary deficiency’ which causes a prominent lower lip and overhanging nose.

Habsburg inbreeding lead to mandibular prognathism. (Richardkiwi / Public Domain)

Habsburg inbreeding lead to mandibular prognathism. (Richardkiwi / Public Domain )

The End Of The Breeding Line

Mandibular prognathism was discovered to have been most pronounced in Philip IV , King of Spain and Portugal from 1621–1640 AD, but the greatest degree of ‘maxillary deficiency’ was found in five members of the family “Maximilian I, his daughter Margaret of Austria, his nephew Charles I of Spain, Charles' great-grandson Philip IV, and Charles II of Spain”. An account in the Daily Mail says that based on their new observations the researchers detected a correlation between mandibular prognathism and maxillary deficiency which suggests a shared genetic basis, and that Habsburg jaw should be considered to cover both conditions.

Engraving of Margaret of Austria of the Habsburg dynasty. (Hansmuller / Public Domain)

Engraving of Margaret of Austria of the Habsburg dynasty. (Hansmuller / Public Domain )

The team had studied 11 portraits to get this far, but to assess the actual degree of inbreeding among members of the Habsburg family the team looked at the dynasty's wider family tree and more than “6,000 individuals making up some 20 generations” were considered. Professor Vilas and colleagues ultimately found a strong relationship between the amount of inbreeding and each Habsburg's degree of mandibular prognathism.

The cause of the proposed relationship between inbreeding and the Habsburg jaw remains unclear but the team speculated that mating occurring between relatives increases the likelihood of children inheriting two identical forms of one gene, which in effect ‘lowers’ their overall genetic fitness making these children susceptible to extreme recessive traits.

Inbreeding, Or Pure Chance?

In conclusion, while this study is based on known historical figures, Professor Vilas says inbreeding is still common in some geographical regions among some religious and ethnic groups, so it's important today to investigate its effects in the modern world. And the team referred to their study of the Habsburg dynasty as a “kind of human laboratory” because the range of inbreeding was so high. But the researchers admit that having studied such a small number of individuals they cannot rule out the slender chance that the Habsburg jaw's prevalence in that great European royal family came about “by pure chance”.

Philip IV of the Habsburg family was one member who had the greatest degree of maxillary deficiency. (Mayyskiyysergeyy / Public Domain)

Philip IV of the Habsburg family was one member who had the greatest degree of maxillary deficiency. (Mayyskiyysergeyy / Public Domain )

Top image: King Charles II of Spain, was the last Habsburg ruler of the Spanish Empire. He is now best remembered for his physical disabilities. Source: TRAJAN 117 / Public Domain

By Ashley Cowie

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