Celtic probably not from the west

The term "Celtic from the west" is the catchphrase for a working theory, offered in a couple of recent books, positing that the earliest speakers of Celtic languages lived in Atlantic Europe during the Bronze Age or even earlier. It'll be interesting to see how this theory holds up against increasing numbers of ancient samples from attested early Celtic-speaking populations.

More popular and long-standing theories postulate that the Proto-Celts are associated with the Urnfield and/or Hallstatt archeological cultures of Late Bronze Age and Iron Age Central Europe. I'm inclined to agree with these more mainstream views when looking at my qpAdm mixture models below of three Celtiberians from what is now La Hoya, northern Spain, from the recent Olalde et al. paper on the genomic history of Iberia.

Celtiberian_LaHoya
Halberstadt_LBA 0.207±0.077
Pre-Celtiberian_LaHoya 0.793±0.077
chisq 15.031
tail prob 0.522396
Full output

Celtiberian_LaHoya
Halberstadt_LBA 0.196±0.074
Non-Celtic_Iberian 0.804±0.074
chisq 17.366
tail prob 0.362297
Full output

The Celtiberians show a stronger signal of (Urnfield-related?) ancestry from the northeast than their Bronze Age predecessors in northern Iberia (Pre-Celtic_LaHoya) as well as their Iron Age contemporaries from eastern Iberia (Non-Celtic_Iberian). The latter group very likely spoke the non-Indo-European Iberian language. It's not clear what the Bronze Age northern Iberians spoke, but it may have been a language related to Basque, which is also non-Indo-European.

Of course, the fact that the Celtiberians harbored more northern Bell Beaker-related ancestry than basically all earlier Iberian groups was already reported in the Olalde et al. paper (on page 2), but I just wanted to see if I could flesh out some more details in regards to this observation by using chronologically and archeologically more proximate reference populations.

See also...

Open thread: What are the linguistic implications of Olalde et al. 2019?

An exceptional burial indeed, but not that of an Indo-European

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

Open thread: What are the linguistic implications of Olalde et al. 2019?

I was going to write a huge post on the linguistic implications of the latest batch of ancient DNA from Iberia courtesy of Olalde et al. 2019, and then I thought better of it. Admittedly, I don't know enough about the languages of prehistoric Iberia to say anything really useful on the topic. So instead here's an open thread to bounce around a few ideas in the comments.

Just briefly, this is what Olalde et al. say in the abstract of their paper about the relationship between ancestry from the Pontic-Caspian steppe and languages in Iron Age Iberia:

We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European–speaking regions but also into non Indo-European–speaking ones, and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia.

However, in the paper it's revealed that "Indo-European regions" actually refers to a Celtic-speaking part of northern Iberia. And it's quite possible that Celts moved into this area from outside of Iberia only during the Iron Age. In other words, the speakers of Indo-European languages here may not have been the descendants of any of the people with steppe ancestry who came to Iberia by ~2000 BCE.

So I'm probably not alone in thinking that the question of the linguistic affinities of these early migrants with steppe ancestry to Iberia (mostly associated with the Bell Beaker culture or BBC) remains open, especially since they evidently had such a profound genetic impact on the later non Indo-European-speaking populations of eastern and southern Iberia. Could they have been the speakers of unattested Indo-European languages, as well as Proto-Iberian and Proto-Basque? If not, why not?

Below is a Principal Component Analysis (PCA) of West Eurasian genetic variation. I highlighted some of the ancient samples from Olalde et al., as well as Basques and other present-day Iberians. The Basques form a tight cluster with most of the Copper, Bronze and Iron Age Iberians, and, unlike the other present-day Iberians, they basically look like an Iberian population from the metal ages. The relevant datasheet is available here.

This is nothing new and very much in line with the results in Olalde et al., but I wanted to emphasize the point that Basques were not just a group that experienced an extreme founder effect in R1b-P312, which is a Beaker-specific Y-chromosome lineage. Rather, they're still very similar to Iberian Beakers in terms of overall genetic structure. So where did they get their language?

See also...

Celtic probably not from the west

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...