Bred in the bone

A while back I had my DNA tested.  I know a good bit about my family tree, and I did it not only to find out about my genetic heritage, but to see if the DNA tests were as accurate as they claim -- a bit like a teacher being able to tell if a student is doing a problem correctly because (s)he already knows what the answer should be.

The answer is: it's pretty damn good.  The most interesting was from a company called My True Ancestry, which supposedly was working off an enormous data bank and could do some seriously fine-grained analysis.  I uploaded my DNA file, and within a few hours I had a map of the closest matches, and they turned out to be spot-on.  It picked up my great-great grandfather Solomon Meyer-Lévy, who was an Ashkenazi Jew from Alsace, and also my father's paternal ancestry, which came from the French Alps.  The rest of my family was scattered through western and northwestern France, England (a cluster in southern England and one in Yorkshire), and two spots in Scotland (one near Glasgow, one near Edinburgh).

This aligns pretty much perfectly with what I know about the origins of my family.  The "pretty much" comes from one puzzling finding; it showed no matches in Germany.  Another great-great grandfather, one William Brandt, came to America in the mid-1800s and married a woman of French and Dutch ancestry named Isabella Rulong.  I know William was German; on the census his birthplace is given as Bremen, so I even know the city.  But my DNA shows zero ancestry in Germany.

However, the answer to this mystery could be simple.  I know a bit about William Brandt because the house he built in the 1870s is on the Louisiana Register of Historic Homes.  William was the court recorder for Lafayette Parish for almost twenty years, and served as mayor for a year.  But the woman who now lives in what was Brandt's house gave us a tour and told us a little about what she knows about my ancestor, and apparently he wasn't exactly a pinnacle of exemplary behavior.  He was, she said, a notorious drunkard, frequently having to be rescued from some ditch or another he'd fallen into after his latest night on the town.  

William Brandt's house, Lafayette, Louisiana [Image licensed under the Creative Commons Paigecbroadbent, Brandt, CC BY-SA 3.0]

This may explain why he held the office of mayor for only a year, something that has always intrigued me.  And it may well also account for my lack of German ancestry.  It's entirely possible that my great-great grandmother Isabella found a friend, as it were, to provide solace and comfort in the absence of her ne'er-do-well husband, and this unknown is actually my biological great-great grandfather.  A study two years ago found that about one percent of births worldwide are due to what they euphemistically call "extra-pair paternity," which is why you have to sign a waiver when you get your DNA tested that you won't hold the company responsible if your results aren't quite what you expected.

So I think there's a pretty good chance that my great grandmother, Mary Emily (Brandt) Bonnet, was not actually William's daughter.  Just as well.  I have enough rogues and scoundrels in my family as it is.

It's amazing what we can now figure out by DNA analysis.  A study just published this week in Nature, written by a team of researchers way too long to list here, used DNA samples from bones and teeth found at burial sites in England to see if they could figure out who came from where and when, and found that in the Late Bronze Age (1,200 to 800 B.C.E.) there was a huge influx of people from what is now northwestern France.  These people, who were probably formed of different tribes but are what we usually collectively call "Celtic," eventually replaced fifty percent of the indigenous pre-invasion population.

"By using genetic data to document times when there were large-scale movements of people into a region, we can identify plausible times for a language shift," said study co-author David Reich of Harvard University, in an interview with Science Daily. "Known Celtic languages are too similar in their vocabularies to plausibly descend from a common ancestor 4,500 years ago, which is the time of the earlier pulse of large-scale migration, and very little migration occurred in the Iron Age.  If you're a serious scholar, the genetic data should make you adjust your beliefs: downweighting the scenario of early Celtic language coming in the Iron Age [and early Bronze Age] and upweighting the Late Bronze Age."

England, of course, has been invaded and settled several times since then; by the Romans in the first century C.E., by the Germanic Anglo-Saxons starting in the sixth century, then by the Norman French in the eleventh.  Each new pulse of invaders brought along their own languages and culture -- and their DNA.  That we can look at bones today and see the genetic history of the people they came from is pretty stupendous.

One of the coolest pieces of this research has to do with lactose tolerance.  You probably know that lactose is a sugar that is easily digested by most mammals only in infancy, and adults lose their tolerance for it.  (This is why it's not a good idea to feed milk to an adult cat.)  But some people retain the ability to digest lactose -- it's most common in Europe, and is caused by a single gene.  Lactose tolerance seems to have spread along with the practice of keeping dairy cattle, for obvious reasons.  And in the period studied by the research, the incidence of the lactose-tolerance gene skyrocketed, so the new influx of settlers seem to have been milk drinkers -- and brought along their cattle.

It's amazing what we can learn from a bunch of three-thousand-year-old bones, and that the DNA fragments still contained within them give us a window into the movements of people during a time we know little about otherwise.  In my case, we're talking about people who are likely to be my ancestors (all "extra-pair paternity events" aside).  One more example of the wisdom in the saying carved into the wall of the Temple of Apollo at Delphi: γνῶθι σεαυτόν ("know yourself").

Or, as John Heywood put in in 1546: "What's bred in the bone comes out in the flesh."

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I remember when I first learned about the tragedy of how much classical literature has been lost.  Take, for example, Sophocles, which anyone who's taken a college lit class probably knows because of his plays Oedipus Rex, Antigone, and Oedipus at Colonus.  He was the author of at least 120 plays, of which only seven have survived.  While we consider him to be one of the most brilliant ancient Greek playwrights, we don't even have ten percent of the literature he wrote.  As Carl Sagan put it, it's as if all we had of Shakespeare was Timon of Athens, The Merry Wives of Windsor, and Cymbeline, and were judging his talent based upon that.

The same is true of just about every classical Greek and Roman writer.  Little to nothing of their work survives; some are only known because of references to their writing in other authors.  Some of what we do have was saved by fortunate chance; this is the subject of Stephen Greenblatt's wonderful book The Swerve, which is about how a fifteenth-century book collector, Poggio Bracciolini, discovered in a monastic library what might well have been the sole remaining copy of Lucretius's masterwork De Rerum Natura (On the Nature of Things), which was one of the first pieces of writing to take seriously Democritus's idea that all matter is made of atoms.

The Swerve looks at the history of Lucretius's work (and its origin in the philosophy of Epicurus) and the monastic tradition that allowed it to survive, as well as Poggio's own life and times and how his discovery altered the course of our pursuit of natural history.  (This is the "swerve" referenced in the title.)  It's a fascinating read for anyone who enjoys history or science (or the history of science).  His writing is clear, lucid, and quick-paced, about as far from the stereotype of historical writing being dry and boring as you could get.  You definitely need to put this one on your to-read list.

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

Chewing gum and talking about talking

Earlier this week I looked at three cool archaeological discoveries -- cave art in Indonesia, and two finds in Egypt, one of a bone from someone killed in the battle recorded on the Rosetta stone, and the other about a researcher who found that the practice of tattooing has been around for a very long time.

But we're not done with mind-blowing archaeological stories, apparently, because there are two more that I just found out about, and which (if anything) are even cooler than the ones I wrote about Monday.

I learned of the first one from my friend, novelist and blogger Andrew Butters, whose blog Potato Chip Math is a must-read.  In this one, we find out that a team of geneticists have sequenced the DNA of a girl who lived in Denmark 5,700 years ago...

... from a wad of chewing gum.

Well, technically, it was birch sap, but same idea.  They were able to extract her DNA from the gum and sequence her entire genome, which allowed them not only to figure out what ethnic group she was from, but to make a good shot at her appearance.  She had dark skin and hair, they found, and blue eyes.  Here's an artist's reconstruction of what she might have looked like:

[Reconstruction by Tom Björklund]

The authors write:

Analysis of the human reads revealed that the individual whose genome we recovered was female and that she likely had dark skin, dark brown hair and blue eyes.  This combination of physical traits has been previously noted in other European hunter-gatherers, suggesting that this phenotype was widespread in Mesolithic Europe and that the adaptive spread of light skin pigmentation in European populations only occurred later in prehistory.  We also find that she had the alleles associated with lactase non-persistence, which fits with the notion that lactase persistence in adults only evolved fairly recently in Europe, after the introduction of dairy farming with the Neolithic revolution.

The period she lived in was when northern Europe was taken over by people known as the "Funnel Beaker Culture," so named because of their characteristic narrow-based, highly-ornamented pottery:

The 5,200 year old Skarpsalling vessel [Image is licensed under the Creative Commons Nationalmuseet, Skarpsallingkarret DO-9665 original, CC BY-SA 3.0]

"It is amazing to have gotten a complete ancient human genome from anything other than bone,'' said study lead author, evolutionary geneticist Hannes Schroeder, of the University of Copenhagen, in an interview with Science Alert.  "The DNA is so exceptionally well preserved that we were able to recover a complete ancient human genome from the sample… which is particularly significant since, so far, no human remains have been recovered from the site."

The second story goes back a great deal further in time than the little Neolithic Danish girl, though.  In fact, it kind of crosses the line from archaeology into paleontology, because in a paper in Science Advances we find out that the ability to speak might have been around in primates for twenty million years.

The study, led by Louis-Jean Boë of the University of Grenoble, analyzes the mechanics of human speech, in particular how the morphology of the mouth, trachea, and larynx allow for the production of meaningful sound.  It's been thought for years that the advent of speech occurred when our ancestors' larynxes (voice boxes) gradually moved downward, pulling the back of the tongue backward and downward as well and giving the tongue more mobility to shape sounds.  But what Boë's team found was that even if you accept that as the hallmark of speech, it goes a long way further back than we'd realized.

"First, even among primates, laryngeal descent is not uniquely human," Boë and his team write.  "Second, laryngeal descent is not required to produce contrasting patterns in vocalizations.  Third, living non-human primates produce vocalizations with contrasting patterns.  Thus, evidence now overwhelmingly refutes the long-standing laryngeal descent theory, which pushes back 'the dawn of speech' beyond ~200 ka ago to over ~20 Ma ago, a difference of two orders of magnitude."

So that means that at least from a mechanical standpoint, our distant ancestors had the capacity for speech.  Whether their brains were developed enough to say anything particularly interesting is still a matter of conjecture.  But evolution is all about minuscule gains.  Once the upper respiratory tract becomes capable of modulating sounds in a meaningful way, this puts selective pressure on the brain to refine its ability to understand and convey meaning with those sounds -- which puts pressure on the vocal apparatus to become better at producing subtle differences in sounds, and so on and so forth.  Which, as comedian Paula Poundstone notes, may not be entirely a good thing:

Be that as it may, it's a pretty cool discovery.  As I pointed out in Monday's post, it's incredible how much we can infer about our distant ancestors' appearance, culture, and abilities from evidence that would have been a closed book only ten years ago.  Our techniques for carrying out this research are only going to improve, so keep watching the journals -- my sense is that the amazing discoveries in this field have only just begun.

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This week's Skeptophilia book recommendation is pure fun, and a perfect holiday gift for anyone you know who (1) is a science buff, and (2) has a sense of humor.  What If?, by Randall Munroe (creator of the brilliant comic strip xkcd) gives scientifically-sound answers to some very interesting hypothetical questions.  What if everyone aimed a laser pointer simultaneously at the same spot on the Moon?  Could you make a jetpack using a bunch of downward-pointing machine guns?  What would happen if everyone on the Earth jumped simultaneously?

Munroe's answers make for fascinating, and often hilarious, reading.  His scientific acumen, which shines through in xkcd, is on full display here, as is his sharp-edged and absurd sense of humor.  It's great reading for anyone who has sat up at night wondering... "what if?"

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

Nyeti

Diehard believers in the Yeti -- known in North America as Sasquatch or Bigfoot -- have this tendency when confronted to bring out such dubious evidence as photographs of prints and blurred video footage.

Skeptics, of course, need more than that.  While those could be evidence of the fabled proto-hominin, the fact is that it's all too easy to fake that sort of thing.  In these days of Photoshop, creating absolutely convincing videos or photographs of Bigfoot (or UFOs or ghosts or what-have-you) is child's play.  And given the combination of attention-seeking behavior and desperation by the pro-Sasquatch cadre, it's not to be wondered at that we skeptics look at all this stuff with a wry eye.

"But wait," the squatchers cry.  "We have hard evidence!  In the form of hair, teeth, feces, and so on!"

And, in fact, so they do.  The Messner Mountain Museum (amongst other places) has a variety of bits and pieces from the Himalayas that have been long claimed to be from the fabled Abominable Snowman.

But of course, the problem is, until that claim is evaluated by a trained scientist, it remains conjecture, given that unless you know what you're looking at, a great deal of mammal fur (not to mention mammal shit) all looks kind of alike.

Finally, the museums have acquiesced.  You can see their reluctance; if the samples proved to be from a non-Yeti source, it's kind of an anticlimax, which would be bad for business.  But the demands of science proved persuasive, and they handed over the goods to Charlotte Lindqvist, professor of biological science at the University of Buffalo.

So, without further ado: the samples from the museums turned out to be from...

... eight bears and a dog.

Which is simultaneously expected and a little disappointing.  Being a biologist myself, no one would be happier than me if the Yeti did turn out to be real.  For one thing, it would be highly entertaining to watch the creationists trying to explain that away.  For another, the sheer magnitude of the coolness factor of there being a hitherto-undocumented giant primate species is undeniable.

But alas, Lindqvist has shot down our hopes and dreams.  "Science does not (or at least should not) have an agenda, and I didn't set out to debunk the Yeti myth," Lindqvist said.  "Although we had a hypothesis that they could be bears, the samples we analyzed were of unknown identity to us and we didn't know what to expect...  Our findings strongly suggest that the biological underpinnings of the Yeti legend can be found in local bears."

Or, as my pal and fellow writer Andrew Butters (of the wonderful blog Potato Chip Math) succinctly put it: "Yeti?  Nyeti."

The scientific method wins again, even though the win is a bit of a Pyrrhic victory for us cryptozoology buffs.  We keep hoping for another coelacanth, and the scientists give us eight bears and a fucking dog.

I mean, no disrespect intended toward bears and dogs, which are cool in their own right.  But still.

So I guess it's back to square one, which I have to admit we kind of never left in the first place. There are other cryptids left to search for, but none of the remainder seem all that likely to me.   For example, I just can't take seriously things like the Scottish Kelpie, which is a man-eating horse-headed water creature, who can also shapeshift into a beautiful naked woman.

Call me skeptical, but I just don't think that one will bear out.

Anyhow, if you're a Bigfoot aficionado, sorry to rain on your parade.  But as I've so often said, you can't argue with the facts.  (Well, you can, but you won't succeed, and you'll make yourself look like a damn fool in the process, as the inimitable Melba Ketchum proved when she claimed she'd found Bigfoot DNA, created a journal so she could publish a paper she'd written that no peer-reviewed journal would touch, had a major online meltdown when everyone laughed at her, and thereby torpedoed her own career.)

As for me, I'm on to bigger and better things, like planning a trip to Australia so I can search for the legendary Drop Bear, which has been likened to a "giant carnivorous koala."  I hear they can be dangerous, so I plan on doing what the locals suggest, which is to walk around holding a screwdriver point-up over my head, so if a Drop Bear drops on me, he'll impale himself.  Better safe than sorry.