Echoes of the ancestors

I recently finished geneticist Bryan Sykes's book, Saxons, Vikings, and Celts: A Genetic History of Britain and Ireland, which describes the first exhaustive study of the DNA of England, Scotland, Wales, and Ireland.  From there, I jumped right into The Ghosts of Cannae: Hannibal and the Darkest Hour of the Roman Republic, by Robert L. O'Connell, which looks at one of the bloodiest battles on record -- the nearly complete massacre of the Roman army by the Carthaginians at the Battle of Cannae in 216 B.C.E.  That book, like Sykes's, considers the large-scale movements of populations.  The Carthaginians, for example, were mostly displaced Phoenicians who had intermarried with Indigenous North African people, and then occupied what is now Spain, adding in a Celtic strain (the "Celtiberians").

One thing that made my ears perk up in O'Connell's book is that Hannibal, in his march toward Rome, crossed through Transalpine Gaul, picking up large numbers of Gaulish mercenaries along the way, who of course had their own grudge with Rome to settle.  And his path took him right near -- perhaps through -- the valley up in the Alps containing the capital of the Celto-Ligurian tribe called the Tricorii, a town then known as Vapincum.

The name Vapincum eventually was shortened, and morphed into its current name, Gap, a modern town of forty thousand people.

It also happens to be about ten kilometers from the little village where my great-great-grandfather was born.

My last name was, like the name of Gap, altered and shortened over time.  It was originally Ariey, and then picked up a hyphenated modifier indicating the branch of the family we belonged to, and we became Ariey-Bonnet.  When my great-great-grandfather, Jacques Esprit Ariey-Bonnet, came over to the United States, the immigration folks didn't know how to handle a hyphenated name, and told him he'd have to use Ariey as his middle name and Bonnet as his surname, so all four of his children were baptized with the last name Bonnet, despite the fact that it wasn't his actual surname.

Just one of a million stories of how immigrants were forced to alter who they were upon arrival.

In any case, about three years ago, I had my DNA analyzed, and one of the things I found out was about my Y-DNA signature.  This is passed down from father to son, so I have the same Y DNA (barring any mutations) as my paternal ancestors as far back as you can trace.  And it turns out my haplogroup -- the genetic clan my Y-DNA belongs to -- is R1b1b2a1a2d3, which for brevity's sake is sometimes called R1b-L2.  And what I learned is that this DNA signature is "characteristically Italo-Gaulish," according to Eupedia, which is a great source of information for the histories of different DNA groups.

Distribution of the larger R1b Y DNA haplogroup [Image licensed under the Creative Commons Maulucioni, Haplogrupo R1b (ADN-Y), CC BY-SA 4.0]

What's most interesting is that as far back as I've traced my paternal lineage, they hardly moved at all.  My earliest known paternal ancestor, Georges Ariey, was born in about 1560 in Ranguis, France, only about a kilometer from the village of St. Jean-St. Nicolas where my great-great-grandfather Jacques Esprit Ariey-Bonnet was born three hundred years later.  And the DNA I carry indicates they'd been there a lot longer than that.

I have to wonder if my paternal ancestors were some of the Gauls who were there to see Hannibal's army headed for their fateful meeting with the Romans -- or even if they may have joined them.  The Tricorii were apparently noted for going into battle wearing nothing but body paint, so maybe this accounts for my own tendency to run around with as little clothing as is legally permissible when the weather's warm.  What's bred in the bone comes out in the flesh, as John Heywood famously said.

So then I had to look at my mtDNA haplogroup.  The mt (mitochondrial) DNA descends only from the maternal line, so we all have mtDNA from our mother's mother's mother (etc.).  Each person's mtDNA differs from another's only by mutations that have accrued since their last common matrilineal ancestor, and this can provide an idea of how long ago that was (in other words, when the two lineages diverged from each other).  Simply put, more differences = a longer time span since the two shared a common ancestor, making both mtDNA and Y DNA something geneticists call a molecular clock.  The mtDNA from my earliest known maternal ancestor, Marie-Renée Brault, who was born in 1616 in the Loire Valley of western France, belongs to haplogroup H13a1a.  Once again according to Eupedia, this lineage goes back a very long way -- it's been traced to populations living in eastern Anatolia and the Caucasus, and from there spread through the mountains of Greece, across the Alps, and all the way to western France where my maternal great-great (etc.) grandmother lived.

So that genetic signature was carried in the bodies of mothers and daughters along those travels, then crossed the Atlantic to Nova Scotia, then went back across to France when the British expelled the Acadians in the Grand Dérangement, and crossed a third time to southern Louisiana in the late eighteenth century, finally landing in the little town of Raceland where my mother was born.  My dad's Y DNA took a different path -- staying put in the Celto-Ligurian populations of the high Alps for millennia, and only in the nineteenth century jumping across the Atlantic to Louisiana, eventually to meet up with my mother's DNA and produce me.

It's astonishing to me how much we now can figure out about the movement of people whose names and faces are forever lost to history, echoes of our ancestors left behind in our very genes.  However much I'd like to know more about them -- a forlorn hope at best -- at least I've gotten to find out about the shared heritage of our genetic clans, and can content myself with daydreams about what those long-ago people saw, heard, and felt.

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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!]

Science shorts

After the last three days' depressing posts, I thought it was once again time to retreat to my happy place, which is: cool new scientific research.  So, for your reading entertainment, here are some early-summer shorts.

[Image licensed under the Creative Commons marcore! from Hong Kong, China, Board shorts 4, CC BY 2.0]

No, not those kind of shorts.  The scientific variety.

First, we have some research that appeared last week in the Journal of Applied Research in Memory and Cognition, done by Julia Soares and Benjamin Storm of the University of California.  In their paper, entitled, "Forget in a Flash: A Further Investigation of the Photo-Taking Impairment Effect," what Soares and Storm found that for reasons still unknown, taking a photo of something impairs your ability to remember it -- even if you know that you won't have access to the photo later.

The authors write:

A photo-taking-impairment effect has been observed such that participants are less likely to remember objects they photograph than objects they only observe.  According to the offloading hypothesis, taking photos allows people to offload organic memory onto the camera's prosthetic memory, which they can rely upon to “remember” for them.  We tested this hypothesis by manipulating whether participants perceived photo-taking as capable of serving as a form of offloading.  In [our] experiments, participants exhibited a significant photo-taking-impairment effect even though they did not expect to have access to the photos.  In fact, the effect was just as large as when participants believed they would have access to the photos.  These results suggest that offloading may not be the sole, or even primary, mechanism for the photo-taking-impairment effect.

The authors were interviewed by Alex Fradera for the Research Digest of the British Psychological Society, and there's a possible explanation for the phenomenon, although it's still speculative.  Fradera writes:

Soares and Storm have a speculative second interpretation.  They suggest that the effort involved in taking a photo – getting the framing right, ensuring the lens is in focus – leads to the sense that you’ve done a good job of encoding the object itself, even though you have been focusing more on peripheral features.  So you’re not mentally slacking-off because you think the camera has it covered – but because you think you already have.  It may be relevant that people who take photographs at events report afterwards feeling more immersed in the experience, which would tally more with this explanation than the disengagement-due-to-fiddling idea.  In any case this is further evidence that those of us who approach exciting life events through the lenses of our electronic devices may be distancing ourselves from fuller participation.

From the Department of Geophysics at the University of Texas comes a study of the most famous (although not, by a long shot, the largest) mass extinction event -- the Cretaceous-Tertiary Extinction of 65 million years ago, which took out the dinosaurs, with the exception of the ancestors of today's birds.  The accepted explanation of the event is a collision by a massive meteorite near what is now the Yucatán Peninsula, forming the Chicxulub Crater.

A long-unanswered question about mass extinctions such as this one is how fast life rebounded.  The problem is that the difference between a thousand, ten thousand, and a hundred thousand years in the geological record isn't that great, so the error rate for any estimates were bound to be high.  But now, geophysicists Chris Lowery, Gail Christeson, Sean Gulick, and Cornelia Rasmussen, working with Timothy Bralower, a micropaleontologist at Pennsylvania State University, have found evidence that narrows that window down -- and surprisingly, shows that life recovered pretty quickly.

The key was finding a sediment core that contained 76 centimeters of brown limestone that came from the years immediately following the impact.  It contained debris from the event, including crystals of "shocked quartz" (quartz crystals showing signs of sudden, extreme temperatures and pressures).  And what the researchers found was that a little as a few thousand years, the ecosystem was beginning to rebound.

"You can see layering in this core, while in others, they’re generally mixed, meaning that the record of fossils and materials is all churned up, and you can’t resolve tiny time intervals," Bralower said.  "We have a fossil record here where we’re able to resolve daily, weekly, monthly, yearly changes."

Speaking of catastrophes, a fascinating piece of research from Stanford University anthropologists Tian Chen Zeng, Alan Aw, and Marcus Feldman gives us a possible explanation for a peculiar calamity that the human race experienced only seven thousand years ago.  By analyzing the genetic diversity among human Y-chromosomal DNA (inherited only father-to-son) and comparing it to the diversity in mitochondrial DNA (inherited only mother-to-child), they found something decidedly odd; the data suggested a serious genetic bottleneck -- but one that affected only males.

The difference was huge.  Zeng et al. showed that the disparity would only make sense if there was a point about seven thousand years ago when there was one male with surviving descendants for every seventeen females.

Feldman writes, in a press release to EurekAlert!:

After the onset of farming and herding around 12,000 years ago, societies grew increasingly organized around extended kinship groups, many of them patrilineal clans - a cultural fact with potentially significant biological consequences. The key is how clan members are related to each other.  While women may have married into a clan, men in such clans are all related through male ancestors and therefore tend to have the same Y chromosomes.  From the point of view of those chromosomes at least, it's almost as if everyone in a clan has the same father. 

That only applies within one clan, however, and there could still be considerable variation between clans.  To explain why even between-clan variation might have declined during the bottleneck, the researchers hypothesized that wars, if they repeatedly wiped out entire clans over time, would also wipe out a good many male lineages and their unique Y chromosomes in the process.

So as weird as it sounds, if you go back a few thousand years, we all have far fewer unique male ancestors than unique female ancestors.


Last, I would be remiss if I didn't make at least a brief mention of research that appeared in the Journal of Clinical Endocrinology and Metabolism last week.  Authored by Audrey J. Gaskins, Rajeshwari Sundaram, Germaine M. Buck Louis, and Jorge E. Chavarro, the paper was entitled "Seafood Intake, Sexual Activity, and Time to Pregnancy," and amongst its conclusion was that the quantity of seafood eaten correlates positively with the number of times per month people have sex.

The researchers speculate that the reason may be the higher quantity of long-chain omega-3 fatty acids, common in seafood, has an effect on the reproductive hormones, increasing sex drive.  It does, however, make me wonder how anyone thought of correlating these, but my puzzlement is probably indicative of why I never went into research.

In any case, I thought it was interesting.  And makes me glad I brought leftover scampi for lunch.  Hope springs eternal, you know?

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This week's recommended book is one that blew me away when I first read it, upon the urging of a student.  By groundbreaking neuroscientist David Eagleman, Incognito is a brilliant and often astonishing analysis of how our brains work.  In clear, lucid prose, Eagleman probes the innermost workings of our nervous systems -- and you'll learn not only how sophisticated it is, but how easy it can be to fool.

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.