Friday, September 24, 2010

Our Ancestor Charlemagne: Taller than Average?

 
John Hawks found a paper analyzing the height of Charlemagne (742-814). Rühli et al. (2010) looked at measurements of Charlemagne's left tibia in order to determine his total height and robustness. The result indicates that he was 1.84 m tall (6' 0"). This is considerably taller than the average height of his male contemporaries at 1.69 m (5' 6"). Thus Charlemagne was taller than 99% of the men around him and qualifies as "great" in more ways than one.

The average height of Germans today is 1.78 m (5' 10") and Belgians are a bit taller at 1.795 (5' 10½"). (Charlemagne comes from the area around Liege in Belgium and Aachen in Germany.) Charlemagne would be taller than average in today's society but not notably taller.

The average height of Europeans (men and women) has increased by about 9-10 cm (3½-4") over 1200 years. This isn't as much as most people believe but it's still significant. (Most people who have visited Medieval Castles take note of the small doorways and assume that contemporary Europeans could pass through them without bending over. Not true—they also had to stoop to get through.)

Is this height increase due to evolution or better nutrition? When presenting this question to my students, I point out that you can only answer the question if you have a good definition of evolution. The definition of evolution I prefer is, "Evolution is a process that results in heritable changes in a population spread over many generations." The key word here is "heritable." In order for average height to be an example of evolution you have to show that the genetic composition of today's European population is different from that of 1200 years ago. In other words, a change in frequency of "tallness" alleles accounts for the change in height.

That's not very likely, so we're not talking about evolution here.

Recall that Charlemagne is almost certainly your ancestor as long as you have some Europeans in your family tree [Are You a Descendant of Charlemagne?]. I happen to know how I'm connected to Charlemagne [My Family and Other Emperors] but he's almost certainly your ancestor even if you don't do genealogy.

Does that mean we all descend from a taller-than-average 9th century European therefore it's no surprise that all Europeans are taller today? No it doesn't mean that at all. Charlemagne is your ancestor—if you are of European descent—but so is everyone else who lived around him. That includes the pig farmer who lived in Herstal, and the midwife in Aix-la-Chapelle. They were average people. Some of them were much shorter than average.


[Hat Tip: John Hawks: Charlemagne the Tall.

Rühli, F.J., Blümich, B., and Henneberg, M. (2010) Charlemagne was very tall, but not robust. Economics & Human Biology 8:289-290. [doi:10.1016/j.ehb.2009.12.005]

10 comments :

  1. Not too bad though when you remember that his dad was 'Pepin the Short'.

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  2. While cleaning up spam I accidently deleted a very important comment by Allan Miller. Here it is.

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    Allan Miller

    "Evolution is a process that results in heritable changes in a population spread over many generations."

    I hate to be picky (internet definition wars can become as tedious as the rantings of DM), but why include the process? And why multiply up the generations - how many is many?

    The processes that cause a phenomenon can be distinguished from the phenomenon itself. I'd argue that evolution is the change that can be observed both population-wide and by following lines of ascent from a particular node on a family tree.

    How 'bout "Evolution is the heritable change in a population over successive generations."?

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  3. Allan Miller proposes,

    I hate to be picky ...

    How 'bout "Evolution is the heritable change in a population over successive generations."?


    I don't have a problem with that definition.

    I'm surprised by the objections to the word "process." Apparently there are a lot of people who react quite negatively to the idea that evolution is a process. I don't know why. What else could it be?

    The reason for inserting "over many generations" in my definition is to avoid the trivial case where the mere appearance of a mutation counts as evolution. If you prefer "successive generations" then that's fine with me.

    Although it does seem picky. :-)

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  4. Larry,

    Well, it certainly is a process, but to many people it is the result of the process as well.

    Evolution (in a general sense) is just change. We are interested both in change in allele frequency (which is a process, or rather a set of subprocesses: mutation, recombination, selection, drift, migration, isolation) and the phenomenon of difference we see when we compare a given 'node' on a web of descent with another.

    I guess an analogy might be stop-frame animation. If we filmed the whole thing, we would just see a lot of people fiddling about with plasticine and the occasional flash - the process. The result is a series of freeze-frames sampling the process, showing change, rather than the process itself. Sample organisms are 'freeze-frames', and their change in descent isn't a process in itself, but evolution of form or function: the result of a process.

    Sorry; I'll stop being picky now! :0)

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  5. "Charlemagne is your ancestor—if you are of European descent—but so is everyone else who lived around him"

    Everyone? No. Not everyone have children, grandchildren, etc.

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  6. So why didn't our Euro-ancestors build doorways high enough for their own use?

    Did they really expect to have to fight invaders coming through every interior room? Or was concussion a rite of passage?

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  7. How uniform is the interbreeding that leads to the conclusion that most Europeans have Charlemagne as an ancestor? I would guess that certain groups like Jews, Basques, and Gypsies are less likely to have Charlemagne as an ancestor due to centuries of parital segregation. Is this enough to change the conclusion?

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  8. It's true that modern European Jews, Basques, and the Romani may have no other Europeans among their ancestors in the past 1000 years.

    True, but highly unlikely.

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  9. Interesting post. I also wonder, considering people mated with those close by, how we can have all Europeans from 800 as our ancestors? I also wonder how isolated the social classes were?

    Is it because he had so many children? But you implied that he is not a special case, and we are all related to the pig farmer as well. Is there a simulation program on-line to help us visualize this?

    I know the theoretical ancestors are in the trillions and 25 million in 800 is much smaller but I always assumed people are pretty inbred anyway. Isn't that how there got to be localised phenotypic differences? What is the average number of actual ancestors in 800?

    By the way I like the idea of not calling evolution a process;)

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  10. Isabel asks.

    Interesting post. I also wonder, considering people mated with those close by, how we can have all Europeans from 800 as our ancestors?

    The "nobility" had to mate with people who were farther away because they didn't mix mix with the local lower classes. That provided a significant amount of gene flow. At some point in our ancestry we all connect to the European nobility and hence to Charlemagne.

    I also wonder how isolated the social classes were?

    They were quite isolated but not completely so. From time to time a former member of the nobility—the third son of a third son of a third son—fell down into the "lower classes." There have also been a few (maybe more) examples of male nobility "mating" with females from the lower classes. :-)

    But you implied that he is not a special case, and we are all related to the pig farmer as well.

    I was wrong. We are only related to a subset of people alive in 800 because some of them didn't have children or grandchildren.

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