Escapees from Siberia

As you might expect from someone who is passionately interested in genealogy, linguistics, and evolutionary genetics, when there's a study that combines all three, it's a source of great joy to me.

This was my reaction to a study in Nature on the evolutionary history of humans in northern Europe, specifically the Finns.  Entitled, "Ancient Fennoscandian Genomes Reveal Origin and Spread of Siberian Ancestry in Europe," it was authored by no less than seventeen researchers (including Svante Pääbo, the Nobel Prize-winning Swedish biologist who is widely credited as founding the entire science of paleogenetics) from the Max Planck Institute, the University of Helsinki, the Russian Academy of Sciences, the Vavilov Institute for General Genetics, and the University of Turku.

Quite a collaborative effort.

It's been known for a while that Europe was populated in three broad waves of settlement.  First, there were hunter-gatherers who came in as early as forty thousand years ago, and proceeded not only to hunt and gather but to have lots of hot caveperson-on-caveperson sex with the pre-existing Neanderthals, whose genetic traces can be discerned in their descendants unto this very day.  Then, there was an agricultural society that came into Europe from what is now Turkey starting around eight thousand years ago.  Finally, some nomadic groups -- believed to be the ancestors of both the Scythians and the Celts -- swept across Europe around 4,500 years ago.

Anyone with European ancestry has all three.  Despite the genetic distinctness of different ethnic groups -- without which 23 & Me genetic analysis wouldn't work at all -- there's been enough time, mixture, and cross-breeding between the groups that no one has ancestry purely from one population or another.

Which, as an aside, is one of the many reasons that the whole "racial purity" crowd is so ridiculous.  We're all mixtures, however uniform you think your ethnic heritage is.  Besides, racial purity wouldn't a good thing even if it were possible.  That's called inbreeding, and causes a high rate of homozygosity (put simply, you're likely to inherit the same alleles from both your mother and father).  This causes lethal recessives to rear their ugly heads; heterozygous individuals are protected from these because the presence of the recessive allele is masked by the other, dominant (working) copy.  It's why genetic disorders can be localized to different groups -- cystic fibrosis in northern Europeans, Huntington's disease in people whose ancestry comes from eastern England, sickle-cell anemia from sub-Saharan Africa, Tay-Sachs disease in Ashkenazic Jews, and so on.

So mixed-ethnic relationships are more likely to produce genetically healthy children.  Take that, neo-Nazis.

Map of ethnic groups in Europe, ca. 1899  [Image is in the Public Domain]

In any case, the current paper looks at the subset of Europeans who have a fourth ancestral population -- people in northeastern Europe, including Finns, the Saami, Russians, the Chuvash, Estonians, and Hungarians.  And they found that the origin of this additional group of ancestors is all the way from Siberia!

The authors write:

[T]he genetic makeup of northern Europe was shaped by migrations from Siberia that began at least 3500 years ago.  This Siberian ancestry was subsequently admixed into many modern populations in the region, particularly into populations speaking Uralic languages today.  Additionally... [the] ancestors of modern Saami inhabited a larger territory during the Iron Age.

The coolest part is that this lines up brilliantly with what we know about languages spoken in the area:

The Finno-Ugric branch of the Uralic language family, to which both Saami and Finnish languages belong, has diverged from other Uralic languages no earlier than 4000–5000 years ago, when Finland was already inhabited by speakers of a language today unknown.  Linguistic evidence shows that Saami languages were spoken in Finland prior to the arrival of the early Finnish language and have dominated the whole of the Finnish region before 1000 CE. Particularly, southern Ostrobothnia, where Levänluhta is located, has been suggested through place names to harbour a southern Saami dialect until the late first millennium, when early Finnish took over as the dominant language.  Historical sources note Lapps living in the parishes of central Finland still in the 1500s.  It is, however, unclear whether all of them spoke Saami, or if some of them were Finns who had changed their subsistence strategy from agriculture to hunting and fishing.  There are also documents of intermarriage, although many of the indigenous people retreated to the north...  Ancestors of present-day Finnish speakers possibly migrated from northern Estonia, to which Finns still remain linguistically close, and displaced but also admixed with the local population of Finland, the likely ancestors of today’s Saami speakers.

Which I think is pretty damn cool.  The idea that we can use the genetics and linguistics of people today, and use it to infer migratory patterns back forty thousand years, is nothing short of stunning.

Unfortunately, however, I have zero ancestry in Finland or any of the other areas the researchers were studying.  According to 23 & Me, my presumed French, Scottish, Dutch, German, and English ancestry was shown to be... French, Scottish, Dutch, German, and English.  No surprise admixtures of genetic information from some infidelity by my great-great-grandmother with a guy from Japan, or anything.

On the other hand, I did have 284 markers associated with Neanderthal ancestry.  Probably explaining why I like my steaks medium-rare and run around more or less naked when the weather's warm.  Which I suppose makes up for my lack of unexpected ethnic heritage.

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Language injection

Two of my biggest interests are genetics and linguistics, so when there's a study that combines the two, it makes my little heart go thumpety-thump.

I found out about a recent one yesterday from a friend and long-time reader of Skeptophilia, and it is a pretty cool intersection between the two fields.  The paper on the research, called "The Arrival of Siberian Ancestry Connecting the Eastern Baltic to Uralic Speakers Further East," was authored by a team led by Lehti Saag of the Department of Evolutionary Biology at the University of Tartu (Estonia), and found that an input of migrants from Siberia into northeastern Europe coincided with the diversification of the Finnic languages (Finnish, Estonian, and Hungarian).  This supports the relationship between the Finnic languages and the Yukaghir languages -- a small family of languages spoken in eastern Siberia.

[Image licensed under the Creative Commons ExRat, Finnic languages, CC BY-SA 4.0]

The team came to this conclusion after analyzing the DNA from 33 skeletons dated from 1200 B.C.E. to 1600 C.E., which allowed them to see how the genetics changed due to the infusion of migrants.

What's interesting is when this happened -- the first millennium B.C.E., which is a lot later than I would have expected (not that my opinion means much; my area of linguistic research in graduate school focused on Scandinavian and northern Germanic languages).  The newcomers from Siberia intermarried with the pre-existing western European populations, resulting in today's Finns, Estonians, and Hungarians:

Our findings are consistent with [Bronze-Age Estonia] receiving gene flow from regions with strong Western hunter-gatherer (WHG) affinities and [Iron-Age Estonia] from populations related to modern Siberians.  The latter inference is in accordance with Y chromosome (chrY) distributions in present day populations of the Eastern Baltic, as well as patterns of autosomal variation in the majority of the westernmost Uralic speakers.  This ancestry reached the coasts of the Baltic Sea no later than the mid-first millennium BC; i.e., in the same time window as the diversification of west Uralic (Finnic) languages.  Furthermore, phenotypic traits often associated with modern Northern Europeans, like light eyes, hair, and skin, as well as lactose tolerance, can be traced back to the Bronze Age in the Eastern Baltic.

"Since the transition from Bronze to Iron Age coincides with the diversification and arrival time of Finnic languages in the Eastern Baltic proposed by linguists, it is plausible that the people who brought Siberian ancestry to the region also brought Uralic languages with them," Saag said, in an interview with Science Daily.  "Studying ancient DNA makes it possible to pinpoint the moment in time when the genetic components that we see in modern populations reached the area since, instead of predicting past events based on modern genomes, we are analyzing the DNA of individuals who actually lived in a particular time in the past."

When they merged with the indigenous population, it injected this Siberian DNA signature into a population that already had its own distinct characteristics.  "The Bronze Age individuals from the Eastern Baltic show an increase in hunter-gatherer ancestry compared to Late Neolithic people and also in the frequency of light eyes, hair, and skin and lactose tolerance," said Kristiina Tambets, also of the University of Tartu.  "We see these characteristics continuing amongst present-day northern Europeans."

The coolest thing about this is that a study of DNA extracted from skeletons can shed light on how languages have changed.  I'd love to see this done elsewhere -- especially in places where there are linguistic isolates, which are languages that seem to be unrelated to any other extant languages.  (Examples are Ainu, Basque, Korean, Etruscan, and Vedda.)  These intersections in research have resulted in some fascinating answers to previously unsolved questions -- and show us again that understanding the past is the window to understanding the present.

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I grew up going once a summer with my dad to southern New Mexico and southern Arizona, with the goal of... finding rocks.  It's an odd hobby for a kid to have, but I'd been fascinated by rocks and minerals since I was very young, and it was helped along by the fact that my dad did beautiful lapidary work.  So while he was poking around looking for turquoise and agates and gem-quality jade, I was using my little rock hammer to hack out chunks of sandstone and feldspar and quartzite and wondering how, why, and when they'd gotten there.

Turns out that part of the country has some seriously complicated geology, and I didn't really appreciate just how complicated until I read John McPhee's four-part series called Annals of the Former World.  Composed of Basin and Range, In Suspect Terrain, Rising from the Plains, and Assembling California, it describes a cross-country trip McPhee took on Interstate 80, accompanied along the way with various geologists, with whom he stops at every roadcut and outcrop along the way.  As usual with McPhee's books they concentrate on the personalities of the people he's with as much as the science.  But you'll come away with a good appreciation for Deep Time -- and how drastically our continent has changed during the past billion years.

[Note:  If you order this book using the image/link below, part of the proceeds will go to support Skeptophilia!]