January 1, 2016

Basque R1b-DF27

Jean sent me a copy of this study (many weeks ago, admittedly), which is an update on the maybe more interesting previous paper by the same UPV-EHU team of June 2015, discussed in this entry.

Patricia Villaescusa et al., Dissection of the DF27 paternal lineage. FSI Genetics 2015. Freely accessibleLINK [doi: http://dx.doi.org/10.1016/j.fsigss.2015.09.172]

Abstract

The genetic evidence provided by the analysis of the Y chromosome is a valuable tool for the study of the evolution of paternal lineages. The dissection of S116, the major M269 subhaplogroup in Western and South-Western Europe uncovered an outstanding frequency of DF27 sublineage in the Basque region. In this study, a dissection of DF27 haplogroup was performed to the highest resolution to date in 340 individuals from the Basque Country. Our results describe frequency distribution patterns for some DF27 sublineages for the first time, and reveal a possible substructure of its paragroups.


And that's basically what it is. They found that Basque R1b-DF27 (70%) mostly belong to two categories: DF27* (31%) and S356 (28%), which are neatly distinct in the neighbor-joining haplotype structure, suggesting to the authors that the remaining DF27* may constitute a yet undescribed subhaplogroup.

Fig. 1. MJN of the DF27 haplogroup in the autochthonous Basque population sample. Two phylogenetic splits into DF27* and S356* paragroups can be observed.

Table 1 lists the frequencies in their Basque sample for a variety of markers under DF27, which includes 70% of Basque Y-DNA lineages. However there's also a significant fraction of R1b-S116* which they only mention by passing:
The high frequencies of DF27* and S116* paragroups indicate a probable existence of new subhaplogroups supporting the subdivision of both of them.

To understand this we have to go back to Valverde 2015, which detected high frequencies of paragroup R1b-S116* among Basques and Irish (but not other Iberians nor Bretons). There is a blank of knowledge about the exact details of R1b-S116 in France but otherwise we have a pretty good idea of the phylogenetic and geographic structure (what I call the "geostructure") of this most important European patrilineage. 

I won't repeat everything (please check the provided link and other links stemming from there for full details) but I will again synthesize what it means here because there is still some people who seems oblivious to factual reality about this haplogroup. An image is worth a thousand words:


My reconstruction of the origins of R1b-S116 based on known 'geostructure'

The three ovals represent very generically the distribution of the three major subclades of R1b-S116 (check the Valverde 2015 maps for full details), the two green stars represent confirmed areas of high R1b-S116* frequencies and the pale green star with the question mark represent possible other such areas in France, particularly an unconfirmed (unsourced) claim on this paragroup being very important at the Massif Central. If you know something more on this fine detail of R1b-S116 in France (or other relevant areas such as Britain, Germany), please share (with references). 

It has been recently known that some Bell Beaker period Irish already carried R1b-M529, what forces the origins of the overall S116 haplogroup to an older date necessarily, at the very least Early Chalcolithic, more likely Neolithic. I'll discuss those findings in an upcoming entry.

Personally I'm tempted for a Dordogne or Greater Aquitaine area of origin, i.e. rather to the West than to the East of the pink delimited region, but cannot be sure with the data we have as of now, particularly the many blanks in France's coverage. 

The claims about this major European lineage being original from Central Europe or even Eastern Europe are totally inconsistent with the data we have: they are nothing but wishful Indoeuropeanist thinking and totally within the realm of pseudoscience.

13 comments:

  1. "Personally I'm tempted for a Dordogne or Greater Aquitaine area of origin, i.e. rather to the West than to the East of the pink delimited region, but cannot be sure with the data we have as of now, particularly the many blanks in France's coverage."

    Why do you think there is an "origin" rather than a widely distributed "zone" for early R1b?

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    1. The most obvious reason is that there was a first man to carry the S116 mutation who is necessarily the patrilineal ancestor to all those carrying it today. The actual expansion "core" necessarily requires more than just one man but that's what you get with his descendants a few generations away, which would still be part of a single population one way or another. A population where this lineage had got fixated (or quasi-fixated) expanded, producing the various branches, which in turn correspond to a single derived ancestor.

      A problem for a distributed zone would be that other lineages would also be at play and they would have got into the founder effect lottery with similar chances, so we would not be talking of a single haplogroup.

      Feel free to discuss because this is admittedly a bit complicated to grasp and I may miss something, but the simplest element here is that there was an S116 biological "partiarch" and then several "sub-patriarchs", so there must be some sort of homogeneity to this expansion, particularly when we consider the high frequencies achieved in most of its destinations (totally founder effect).

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  2. "but the simplest element here is that there was an S116 biological "partiarch" and then several "sub-patriarchs", so there must be some sort of homogeneity to this expansion, particularly when we consider the high frequencies achieved in most of its destinations (totally founder effect)."

    Sure. But many lines of evidence suggest that R1b derived lineages were associated with pastoralism and are then inherently mobile. So it shouldn't be surprising that these lineages might have moved back and fourth, and maintained loose contact networks. I don't think you can so easily fix R1b expansions to particular regions. For instance, it shouldn't be at all surprising that some of the Basque related R1b lineages are also turning up in the British Isles.

    Who's to say though, that there was a unidirectional expansion? Maybe they maintained contact and even moved back and fourth for quite some time.

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    1. I don't see any reason to think that blank slate statements such as "R1b derived lineages were associated with pastoralism" make any sense. There's no clear cut pastoralism vs farming in Europe: both aspects complement each other all the time. Also different peoples adopted more exclusive pastoralism at times because it fit their ecology, regardless of lineage. But in any case in the context of Europe I don't see any obvious relation with that type of economy. Additionally pastoralists living in mostly agricultural areas, as is the case of Europe, tend to leave a scattered trail, not to produce massive impacts, see for example Aromanians: they do move a lot but they don't really make any major impact.

      "I don't think you can so easily fix R1b expansions to particular regions".

      I follow this methodology for all haplogroups: it's not about R1b (or more exactly R-S116) but a method that applies to any haplogroup: know the phylogeny and how it is distributed on the geography and from that you can easily infer a most plausible area of origin. Based on that (and some complementary archaeology) I knew long before the Mal'ta boy was sequenced that Native Americans had began their journey (Y-DNA-wise) in West Asia and journeyed through Central Asia and Siberia eastwards, just because that's what the "geostructure" of Q (and mtDNA X2) pointed to. It's a method of general application and very reliable in my opinion, of course there's always a small uncertainty.

      "Maybe they maintained contact and even moved back and fourth for quite some time".

      Of course. That's perfectly possible. But that does not change the basic "geostructure" and most probably affects to smaller frequency lineages, rather than the big founder effect ones.

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  3. "There's no clear cut pastoralism vs farming in Europe: both aspects complement each other all the time."

    From an archaeological perspective, there certainly is, especially for the Basque region.

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    1. Which one? AFAIK pastoralism and agriculture reached the area simultaneously, as happens in all Europe, at least West of the steppe.

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    1. Feel free but if it is content discussion, I prefer it here, else on 1-on-1 discussions I often feel I'm wasting my time by whispering.

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  5. This comment has been removed by a blog administrator.

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    1. ^^ Nasty troll-stalker. Absolutely banned in my turf.

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  6. My family is from Scotland, where DF27 is 1-5% and I'm R-BY3329. Any idea how that strain got there?

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    1. We do not know for sure but the lineage DF27 (paragroup DF27* particularly) does exist in Ireland and the name "Scot" corresponds to an early medieval Irish tribe, which invaded Scotland and imposed the Gaelic language and also gave it its modern name. It's a possible source, although it can be older too.

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