The great Roman historian Tacitus begins the Germania by discussing how the Germans are separated from certain peoples by mountains, and separated from other peoples by rivers -- and where there were no rivers or mountains, the peoples were separated by Fear.
A similar, intangible concept applies today, to understanding why R1b is so common in Western Europe. Some of it can be gleaned by archaeology, some of it can be gleaned by DNA -- and where archaeology and DNA cannot provide an answer, we must resort to what makes us human: Logic.
Below is a review of all of possible models explaining why R1b and its subclades are common throughout Western Europe. After reading it, you decide which is the most logical.
1. The Bronze-Age Badasses.
The theory goes:R1b males were an awesome military force, who swept through Europe and killed the overwhelming majority of other males in their path. They started in modern Ukraine as bad-ass horsemen. But by the time they got to the coasts, they turned into bad-ass sailors and navigators. These horsemen built boats, and Ireland and England were next to be mowed down by their genocidal awesomeness. Despite traveling the length of Europe, they were still pure R1b by the time they reached Ireland. Sufficiently that some counties in Ireland are 80-98% R1b today. This R1b Empire was the largest that Europe ever knew. Not even Caesar's stretched from Ireland to Ukraine! Even though there was plenty of open space in Europe (the population being less than 1/1000th of what it is today), they decided to conquer an empire this vast expanse and risk the lives of themselves and their children, just because they were such badasses. They were such efficient killers they left no trace in archaeological records in Western Europe of destruction or razing. Despite well-established standards for evolution of language, the empire spoke vastly different languages (i.e. Latin and Ukrainian), despite this all happening just 1000 years or so before the beginnings of Rome and Greece.
Believe it or not, this theory is favored by some people today, who just happen to be R1b males.
2. The Irresistible Indo-Europeans
This theory goes: R1b males had uniformly gorgeous looks, tremendous wealth, and all-star qualities that made all hunter-gatherer women swoon with delight. Whether they had bright red hair, or looked like James Buchanan, cavewomen of all groups throughout Europe dropped their guys and decided to procreate with these R1b studs. None of the local guys resisted. They too were enamored by the R1b good looks, and some kind of genetic superiority that made them and their genes irresistible.
Believe it or not, this
theory is favored by some people today. No, really. They actually posted it in comments below. And they just happen to be R1b
3. Colonizing Conquistadores
This theory is a variation of theory 1, minus the genocide. The theory is: just model the R1b spread after that of the Spanish conquest of the New World. Nevermind that the Spanish had guns, germs, and steel. Nevermind that they had cannon, smallpox, and boats that could traverse oceans. Nevermind that in most places in Latin America, the native haplogroups like Q and C still dominate. Just ignore these things and model R1b after the Spanish.
4. Lactase Persistence
At last we enter the realm of the plausible.
This theory goes as follows: very basal subclades of R1b were present throughout Europe in tiny pockets for a very long time.
This is why a slightly more downstream clade of R1b*, ancestral to modern lineages, was found, already in Els Trocs Spain, 7000 years ago.
I mean think about it. He couldn't have flown there. And in 5100 BC, he couldn't have even ridden a horse.
We know that R1 originated in Eurasia, and that it was present on both ends of Europe by 5100 BC.
If you adopt regular migration theories for on-foot migrations, these very basal R1b people in Spain were likely present in small pockets throughout Europe by 6000 BC. Perhaps in the modern Czech Republic, perhaps in France, perhaps in modern Germany. We only have ~400 aDNA samples from this epoch, and a smaller percentage of them have been tested for Y DNA.
Perhaps they lived in a moist climate less likely to preserve remains. Perhaps they cremated their dead. Perhaps archaeologists ignore their tiny region. But one thing is certain: Basal R1b was present in Europe, end to end, by about 6000 BC.
At some point, during a period of profound starvation, Western Europeans evolved a tremendous caloric advantage: the ability to digest milk. No more killing the cow to eat and therefore live: you can live off of turning grass into protein.
Let's assume the first humans to evolve this, living in some nameless, forgotten pocket of Germany or England or France or Spain were majority R1b, then their population would EXPLODE. In a time of mass starvation and famine, those with a caloric advantage would propagate exponentially.
(Perhaps these people come to worship the cow to some degree, creating taboos to killing it, as we see in modern lands, creating idols of bulls, as we saw in many ancient cultures, and creating elaborate drinking vessels in the shape of Bell Beakers -- but I digress...)
The population of Europe at this time was maybe a million people across the whole continent. If you figure that R1b people had a greater fertility rate (more kids per female, less time to wean because of cowmil availability, less time between kids, healthier kids, more kids reaching adulthood to propagate), then the simple math of exponential demography will show that within as few as 200 years, your uniparental markers will dominate the landscape.
It should be noted that the various genes for lactase persistence mirror closely the distribution of R1b-S21 even today.
5. Refugees and Different Cultural Attitudes
If you know a little about history or current events, this one is not hard to imagine. The historical example is the Goths; the modern example is what is happening in Lebanon with Syrian refugees.
People used to think the Goths were bad-ass, uncivilized, warlike,
mighty (insert "supreme" adjective here) Germanic overlords who
conquered much of the Roman world. But anyone who knows the history
understands that the truth is a little kinder to them (kinder,
depending on if you believe being peaceful and not purposefully killing
people is a good thing).
The Goths were not some mighty tribe hell-bent on destruction, who
willfully took over the Roman Empire. Just the opposite: they started
out from modern South Sweden because of FAMINE. They were so weak,
they were forced to WANDER for centuries. Finally, they invaded the
Roman Empire, because the Huns EVICTED them from their steppe lands in
In other words, one of the baddest-ass people in most people's minds
were refugees, forced to emigrate not because they wanted to conquer,
but because they themselves had been evicted from their homelands by
famine (first) and then another people (the Huns).
If that is too hard on you, let's imagine something happening
today. The population of Lebanon is about 2 million people. Aside
from the districts controlled by terrible people, many of the coastal
folks are pretty wealthy, modern, and diverse. They don't have
extraordinarily high birthrates.
All hell has broken loose near them, in a country you may have heard a
lot of recently. It's called Syria. In the last two years,
Lebanon...has been swamped with 2 million Syrian refugees.
In other words, the population of the country has doubled, in a generation, from an influx of refugees.
Now imagine the Lebanese bear Haplogroup L, we will call it. Imagine
like many wealthier people today, they're not having 20 kids each. More
like 1 or 2.
Imagine the Syrian refugees bear Haplogroup S, we will call it.
Imagine like many poorer people today, they DO have many kids...
The "old" samples within this area we call Lebanon will all be
Haplogroup L. A future archaeologist would find that to be the case.
The "new" samples, after a few generations, will be like 75-25%, with
Haplogroup S clearly "winning out." The cause is a mix of migration --
plus different cultural attitudes toward having kids.
Did the Syrian refugees "conquer" the Lebanese? (No.)
Is it safe to say that the Syrian refugees genes were "selected for?" (No).
That the Syrian men were "more attractive" to women? (No).
That they bore some kind of genetic advantage, that made them fitter? (Again, no.)
6. Different Starting Population Sizes, Different In Time
This one is the hardest to fathom almost, because it is almost circular. It states simply that R1b is the most numerous in Western Europe because they started out more populous, and were the most recent immigrants.
Western Europe is a cul-de-sac for overland migrations. Almost all haplogroups originated in Africa or the Near East, but came into Western Europe via the eastern entry points into Europe. Iberia is the end of the cul-de-sac.
Imagine a 100-acre parcel. At
first, it is a hunting preserve of sorts. It is inhabited by 5 families
who own 20 acres each. They love the deer and geese they harvest from
Next some farmers move in. 50 acres are used for farming. They support 10 farming families, who each have 5 acres.
The land is supporting 5 hunters and 10 farmers. (Have the farmers been "selected for?" No. They are more numerous and more recent migrants).
some others land in the area. There are 100 refugee families or maybe just people who tolerate living close to one another, so
they squeeze into one acre of the land. They have metals, which they
trade for food, so they are able to live in a much smaller parcel.
Have they been selected for? Again, no.
I just described something that has happened in recorded history several times, and surely in prehistory too.
Older, less numerous populations will appear to be "drowned out," unless you are careful. It's just simple math. Those who have been in a locale the longest will be diluted over time.
Many plagues in Western Europe entered through the east. Since R1b-bearing males were the largest migration from the east, it must be considered that different immune systems played a role in their spread.
In sum: R1b could be simply the most common haplogroup in Western Europe because it came there later, in greater numbers, and perhaps as part of a people who had different cultural attitudes toward having children.
In subsequent posts, I will link or recap demographic studies that show the clear power of exponential growth with even tiny differences in birthrates.