Genetic walkabout

Coming hard on the heels of yesterday's post about a woman who claims to be descended from Joseph of Arimathea, today we have some actual valid research, using mtDNA from two-millennium-old teeth in Syria to show that Mesopotamia deserves its moniker "the Cradle of Civilization" -- that same mtDNA signature shows up today as far away as Tibet.

Mitochondrial (mt) DNA is unique in that it always inherits through the matrilineal ancestry.  In other words, you contain the same mtDNA as your mother's mother's mother's etc., as far back as you like to go.  This takes out the role of recombination in your genetic makeup -- the random scrambling of the chromosomes in the nucleus every time they're passed on makes it damn near impossible that the same two parents could produce two genetically identical (non-twin) children.  But with mtDNA, the only differences occur from mutations, which are infrequent -- so this allows us to determine the relationships between different human populations, and track their movements back into prehistory.

My earliest-known matrilineal ancestor, Marie-Renée Brault (born in France in around 1616) had the mtDNA haplotype H13a1a, places her origin in western Europe (which we already knew), and the "H clade" to which she belongs is the commonest mtDNA in Europe.  So no big surprises there.

[Image licensed under the Creative Commons Vanesa Álvarez-Iglesias , Ana Mosquera-Miguel , Maria Cerezo, Beatriz Quintáns, Maria Teresa Zarrabeitia, Ivon Cuscó, Maria Victoria Lareu, Óscar García, Luis Pérez-Jurado, Ángel Carracedo, Antonio Salas, Spatial frequency distribution of different sub-lineages of mtDNA haplogroup H, CC BY 2.5]

Likewise, my two known Native American ancestors, both from the Abenaki tribe of Nova Scotia, were proven as such by their matrilineal descendants having a characteristic "A clade" mtDNA signature, which clearly demonstrates their ethnic heritage -- and their ultimate connection to other A-clade members in Siberia, Korea, and Japan.

The research that got me started on all this is not new, but was new to me; I was sent a link by a friend and loyal reader of Skeptophilia to a paper in PLOS-ONE called, "mtDNA from the Early Bronze Age to the Roman Period Suggests a Genetic Link between the Indian Subcontinent and Mesopotamian Cradle of Civilization," by Henryk W. Witas, Krystyna Jędrychowska-Dańska, and Tomasz Płoszaj (of the University of Łódź), Jacek Tomczyk (of Cardinal Stefan Wyszyński University), and Gyaneshwer Chaubey (of the Biocenter of Estonia).  And in this paper, we find out that an mtDNA type -- haplogroup M4 and M6, which currently are found only in India -- apparently are older than anyone realized, and came from what is now Syria:

Ancient DNA methodology was applied to analyse sequences extracted from freshly unearthed remains (teeth) of 4 individuals deeply deposited in slightly alkaline soil of the Tell Ashara (ancient Terqa) and Tell Masaikh (ancient Kar-Assurnasirpal) Syrian archaeological sites, both in the middle Euphrates valley.  Dated to the period between 2.5 Kyrs BC and 0.5 Kyrs AD the studied individuals carried mtDNA haplotypes corresponding to the M4b1, M49 and/or M61 haplogroups, which are believed to have arisen in the area of the Indian subcontinent during the Upper Paleolithic and are absent in people living today in Syria.  However, they are present in people inhabiting today’s Tibet, Himalayas, India and Pakistan.  We anticipate that the analysed remains from Mesopotamia belonged to people with genetic affinity to the Indian subcontinent since the distribution of identified ancient haplotypes indicates solid link with populations from the region of South Asia-Tibet (Trans-Himalaya).

The amazing part of this isn't so much in the details, but the method.  Mitochondrial DNA extraction from fossilized teeth can give us information about the movement of people back into prehistory. These ancestors of ours, about whom we know virtually nothing -- not their names, their faces, their professions, their cultures -- tell us about their travels by the genetic information carried in their bodies.

Which I find absolutely fascinating.  It's kind of mind-boggling that I carry a bit of DNA in my cells (lots of bits of it, in fact) that originated in the Middle East twenty-thousand-odd years ago, was carried from mother to daughter as these people moved into eastern Europe, crossing the Alps into France, and thence across the Atlantic Ocean to Nova Scotia for over a hundred years -- then back to France after they lost the French and Indian War and got kicked out -- and finally crossed the Atlantic again in 1785 to settle in southeastern Louisiana.

And each of you carry in your own cells pieces of DNA that have equally long, convoluted, and unexpected histories.

Makes you realize that we're all connected, down to the very instructions that built us, and are far more alike than we are different.

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These days, I think we all are looking around for reasons to feel optimistic -- and they seem woefully rare.  This is why this week's Skeptophilia book recommendation of the week is Hans Rosling's wonderful Factfulness: Ten Reasons We're Wrong About the World--and Why Things Are Better Than You Think.  

Rosling looks at the fascinating bias we have toward pessimism.  Especially when one or two things seem seriously amiss with the world, we tend to assume everything's falling apart.  He gives us the statistics on questions that many of us think we know the answers to -- such as:  What percentage of the world’s population lives in poverty, and has that percentage increased or decreased in the last fifty years?  How many girls in low-income countries will finish primary school this year, and once again, is the number rising or falling?  How has the number of deaths from natural disasters changed in the past century?

In each case, Rosling considers our intuitive answers, usually based on the doom-and-gloom prognostications of the media (who, after all, have an incentive to sensationalize information because it gets watchers and sells well with a lot of sponsors).  And what we find is that things are not as horrible as a lot of us might be inclined to believe.  Sure, there are some terrible things going on now, and especially in the past few months, there's a lot to be distressed about.  But Rosling's book gives you the big picture -- which, fortunately, is not as bleak as you might think.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Answers, ignorance, and mitochondrial DNA

Something I fight continuously, as a teacher, is the idea that the most important thing is THE ANSWER.

It's the fault of the way education is usually conducted, of course.  Whether because teachers were themselves taught that way, or because of expediency, THE ANSWER is always considered to be the critical thing.  It doesn't matter how you got there; process isn't the concern.  As long as you have THE ANSWER in the appropriate space, you get full credit.

The problem is, by the time students get to high school, I'm expecting that they'll be moving beyond that, and it's often a battle.  I've had more than one student say, "Just tell me what to write down," as if somehow that was going to engender understanding.  My frustration on this point is what resulted in the following actual conversation:

Student:  What do I write down for question #7?
Me:  Whatever you think the correct explanation is.
Student:  But what if my explanation isn't right?
Me:  Then I'll mark it wrong.
Student:  But I don't want to write down the wrong answer!
Me:  Then don't.

In my own defense, I wasn't simply trying to be snarky; it just gets tiring to know that my refrain of "I will not think for you" often falls on deaf ears.

I find myself wondering how deep this inclination goes, and if it's because as a culture, we're taught to expect that there always is a single correct answer.  The biblical maxim of "Ask and ye shall receive" is pretty deeply ingrained.  We're uncomfortable with not knowing.

We're even more uncomfortable where there may be no way to know.

I ran squarely into this with my genealogical pursuits a couple of days ago.  There's a pair of sisters who were amongst the founding mothers of Acadia (as people of French descent call Nova Scotia).  Their names are Catherine and Edmée LeJeune, and they show up in Acadia in the early 1600s.  (I actually descend, on my mother's side of the family, from both of them.)

No one knows where they were born, or who their parents were.  The early records simply aren't complete enough.  This has led to speculation that they may have been Natives -- there are numerous records of early French settlers marrying Native women.  Could it be that the LeJeune sisters were members of the Mi'kmaq, Maliseet, or some other Native tribe of eastern Canada?

The whole thing was a moot point for decades; like I said, the documentation simply does not exist.  This didn't stop rampant speculation on both sides of the question.  Instead of just leaving their origin as "unknown," people seemed to need to fill in the blank with something.

Then, along came mitochondrial DNA analysis.  mtDNA is only inherited through the maternal line, so any matrilineal descendant of either sister should pinpoint their origin.  Matrilineal descendants (several of them) were traced, offered up blood samples, and the results all agreed; Catherine and Edmée were of the haplotype U6a7a, a signature that is characteristic of North African ancestry.

In my mind, this seemed to settle it.  The Moors made significant inroads into southwestern Europe in the Middle Ages, and there are huge numbers of people in Spain, Portugal, and southern France who have North African ancestry.  Catherine and Edmée most likely were born in France.  But that wasn't good enough; the people who had already decided that they were Native weren't content to let it rest.

Enter Dr. Howard Barraclough "Barry" Fell, professional zoologist and amateur archaeologist and linguist, who in 1976 published a book called America B.C.: Ancient Settlers in the New World.  In it, using the cherry-picking lexicography favored by people who aren't actually trained in linguistic analysis, Fell came to the conclusion that the Mi'kmaq orthography, one of the only pre-Columbian North American writing systems, was descended from none other than...

... ancient Egyptian hieroglyphics.

Now I hasten to state that most linguists consider Fell to be a well-meaning but misguided amateur.  (For a particularly insightful take-down of his conclusions, check out this site, courtesy of linguist and scholar Richard Flavin.)  But this hasn't stopped sites like "Mi'kmaq/Ancient Egyptian Connection" from surfacing, wherein we find that the ancient Egyptians made it not only to Nova Scotia, but all the way to Illinois and... Australia!

Now, I know the Egyptians were pretty cool.  But if you're gonna make a claim like that, I'm gonna need something more than a few chance correspondences between words and symbols before I buy in.

But the "have an answer at all costs" crowd wouldn't let it lie, especially once the Mormons got involved, and used Fell's so-called research to support their contention that the Native Americans were descendants of the Ten Lost Tribes of Israel.

Why can't we just say "we don't know?"  Why can't we focus on the reality -- the Mi'kmaq and other Native groups made their way to North America at some unspecified time in the past, and (more specifically) Catherine and Edmée LeJeune had some North African ancestry somewhere -- and consider how awesome the process of knowing is?  We can actually use blood samples from distant descendants of long-dead individuals to determine the movements of groups of people thousands, or tens of thousands, of years ago.

Cool, no?

Not cool enough, apparently.  We need THE ANSWER.

Now, let me be clear on this: there's something to be said for having a correct picture of what's going on.  But when there's uncertainty, it's critical to be comfortable with a partial answer, and even more critical to understand the whole context of knowledge within which we are working.  In the long haul, I'm happier knowing about mtDNA and the migration of human groups than I would be just to have a final answer to fill in for my distant foremothers' birthplace.

But unfortunately, I appear to be in the minority.