I'm descended from Vikings. People often ask me why I'm so interested in Iceland and the Icelandic sagas--why I write books about the Viking Age. My glib response has been to say, "All my ancestors come from Northern Europe, so I'm sure there was a Viking in there somewhere." But now I can legitimately say I'm descended from a Viking warrior.
For the sake of argument, let's call him Ragnar Lothbrok.
A few months ago, in "The Real Ragnar Lothbrok," a post about the History Channel's Vikings series, I questioned whether there was a historical person called Ragnar Lothbrok or if the character in the stories we know is a conflation of several Vikings with similar names. My source was a new scholarly book by Dr. Elisabeth Ashman Rowe, Vikings in the West: The Legend of Ragnarr Loðbrók and His Sons.
The post inspired two readers to reply that they were descended from Ragnar or from another Viking, "a close companion to Rollo" who founded Normandy, and another to suggest (sarcastically) that he himself descended from Julius Caesar and Cleopatra.
Well, an article in the new science magazine Nautilus by Veronica Green says … they are all right. They do descend from Ragnar, Rollo, Caesar, and Cleopatra. And I do descend from Ragnar Lothbrok.
You do too.
Green reports on a "a computer model of human genetics" that shows "that anyone who was alive 2,000-3,000 years ago is either the ancestor of everyone who's now alive, or no one at all."
Mindboggling as that idea is, it's too far back in time for Ragnar Lothbrok, who lived (if he lived) around 845 AD.
But Green points to an article on the National Geographic blog by Carl Zimmer, which explains that you only need to go back as far as Charlemagne (c. 800 AD) to find that you're related to everyone who lived in Western Europe (if not the world) at that time.
Zimmer was reporting on the work of Yale statistician Joseph Chang. Chang did the math: You have 2 parents, 4 grandparents, 8 great-grandparents, 16 great-great-grandparents … as Zimmer writes, "If you go back to the time of Charlemagne, 40 generations or so, you should get to a generation of a trillion ancestors. That's about 2,000 times more people than existed on Earth when Charlemagne was alive."
So you're related to all of them. Charlemagne, Ragnar, all of them.
Chang's not the only scientist to come to this conclusion, Zimmer notes. A recent paper by Peter Ralph, a geneticist at USC, and Graham Coop, a geneticist at UC-Davis, looked at the DNA of 2,257 people currently living in Europe. (You can read the original paper here: http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001555, or a nice less-technical FAQ-sheet here: http://gcbias.org/european-genealogy-faq/)
Ralph and Coop found that huge chunks of DNA were shared by people who didn't seem like they should be related. As they explain, "We found that even people living on opposite sides of Europe are genealogically closely related to each other over the past thousand years. Even pairs of people as far apart as the UK and Turkey share a chunk of genomic material 20% of the time. Since the chance that two people inherit genetic material from any one shared ancestor from 1,000 years ago is incredibly unlikely (<10-10), to explain such sharing we need these pairs of individuals to share many ancestors. In fact, they need to share a number of ancestors that is far larger than the size of the European population, indicating that any pair of individuals share as ancestors all of the individuals alive back at the time in Europe, each many times over…. Everyone is everyone's ancestor."
As Zimmer puts it, "Charlemagne for everyone!"
Or, as I'd prefer, Ragnar Lothbrok for everyone!
Join me again next Wednesday at nancymariebrown.blogspot.com for another adventure in Iceland or the medieval world.