I must admit that this post I am particularly pleased because it combines two of my passions, biology and history. It is not the first time that genetics comes to the aid of historical research, one must recall the investigations carried out in the 90's on remains of the Russian imperial family and culminated in very recent date, or trying to elucidate if the remains of Christopher Columbus are actually placed in the cathedral of Seville or rest in the Dominican Republic. This time it is the turn to English Habsburgs, the royal family during the sixteenth and seventeenth centuries ruled the destinies of Spain ... and half the world.
A study published a few days ago, conducted by researchers at the University of Santiago de Compostela, relates to this dynasty with inbreeding caused by the large number of arranged marriages between members of the same.
Felipe I el Hermoso, Origin of the House of Austria in Spain (the name given to the Habsburgs Hispanic), along with his wife Joanna of Castile , " la Loca, daughter of the Catholic Monarchs give rise to a new royal family his arrival at the throne of Castile in 1506. Among his children was born Carlos I of Spain, that will access the new English crown in 1516 and is recognized worldwide as the Emperor Charles V to the throne of the German Empire in 1519, his descendants will reign in Spain until 1700, the year the dying Charles II "the Bewitched" without issue, leading to the War of English Succession culminating in the inauguration of the Bourbon French Famila currently prevailing.
Carlos II was dubbed haunted given the enormous amount of suffering from physical defects, had rickets, his head was abnormally large, learned to speak and walk four years to eight. He was apathetic, married twice and got no marriage desdendencia. Apparently he suffered from impotence and premature ejaculation. Blood in the urine and had sporadic episodes of diarrhea and frequent vomiting. Besides suffering edema in the feet, legs, abdomen and face. After a grueling existence died at age 39, looking like a real old man. The text of his autopsy is distressing, " the body was not even a drop of blood, the heart appears the size of a peppercorn corroded lungs, intestines rotting and gangrene, in three large kidney stones, one testicle, black as coal, and a head full of water .
Historians have liked to see in the custom of marriage consanguineous origin of the problems of Charles II. The British Hispanist John Lynch, who specializes in Hispanic Habsburg, said: " Charles II was the last, the most degenerate and most pathetic victim of Habsburg inbreeding .
Family tree of the English Habsburgs, obtained from the original article : Alvarez G, Ceballos FC, Quinteiro C (2009) The Role of Inbreeding in the Extinction of a European Royal Dynasty. PLoS ONE 4 (4): e5174. doi: 10.1371/journal.pone.0005174
Viewing
above diagram shows how it was customary marriage between relatives, Philip II and Philip IV who married his nieces would be a good example. The data show that in the two centuries-long dynasty there were 11 marriages blood. But what are the effects of inbreeding?.
Each of us has a 50% chance of inheriting one of our parents either allele (our mother provides half of our heritage and our father the other half). A brother or sister happens we like, but if we see which is the probability that both have inherited the same allele, then the figure drops to 25%. How important is this?. Well, if we talk about disease-causing alleles, the likelihood of them among family members is greater, and if those relatives have offspring together, the likelihood increases further. The Wright's inbreeding coefficient (F) is used to analyze the degree of consanguinity of a population and is based on the probability that an individual inherits the same allele from his father and his mother from a common ancestor to both. Analyzing the family tree of more than 3ooo Habsburg family members as the scientists found the coefficient F increases over the years, and Philip I, the founder, has an F = 0.025 (2.5%), while Carlos II has a F = 0.254 (25.4%), ten times more, something greater than they would the children of a marriage between siblings.
The fact that the high rate of consanguinity of the last Habsburg king English has to do with his fragile health is supported by two recessive genetic diseases (which is only expressed when an individual inherits an allele simultaneously for the same in each of his parents, a fact that is reinforced by inbreeding) that apparently the monarch suffered. One of them was multiple pituitary hormone deficiency , which is the inability of the pituitary to produce some of your hormones: growth hormone (GH) , which is responsible for growth, the gonadotropins (FSH & LH) , which help in the development of puberty and fertility control, the Thyroid hormone (TSH), that control metabolism, the antidiuretic hormone (ADH ), which controls the amount of urine that is produced, and adrenocorticotropic hormone (ACTH), maintaining a good blood sugar in the blood. The deficit of these hormones lead to short stature, muscle weakness, apathy, impotence, infertility, and gastrointestinal problems, symptoms suffered by all the unhappy Charles II.
The other disease, distal renal tubular acidosis , is caused by excessive secretion of acid in the kidney, resulting in the loss of total body calcium, causing softening and weakening of bones, retarded growth in children, skeletal deformities and muscular weakness. There is also an increase in the presence of calcium in the kidney and kidney stones due to excessive excretion of calcium and phosphate through these organs. These symptoms would complete those presented by the bewitched king .
Authors concluded that although a very low probability that an individual present these two rare genetic diseases simultaneously, it dramatically increases with increasing inbreeding, a fact that we found in our protagonist.
In short, the marriage policy the Habsburg dynasty ended with the same due to the increase in inbreeding occurred, especially with the last of their monarchs Hispanic.
Finally, I leave a card Music Gaspar Sanz, contemporary musician Carlos II, and let me recommend a book of fiction fun and adventure set in the dramatic final months of this king, "King Bewitched " Jose Calvo Poyato .
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