Our results revealed tMRCA average values ranging from 4725 to 1175 years ago and support the estimates of Serre et al. (3000–6000 years ago) , rather than Morral et al. (52,000 years ago) , but the latter figure was challenged by Kaplan et al.  because of disagreement with assumptions used in their calculations. In addition, the tMRCA values from western European regions reported herein refine the results of Fichou et al.  from a study of Breton CF patients in which the Estiage analysis suggested that the most common recent ancestor lived 115 generations ago. That tMRCA value, however, may have underestimated the age of p.(Phe508del) in Brittany due to consideration of all the haplotypes, even those that were reconstructed with ambiguities, as well as a potential bias associated with consanguinity due to including both haplotypes in homozygous families. In the more stringent Estiage analyses reported herein, those potential biases were avoided for all populations, leading to estimates of the oldest tMCRA values corresponding to the Early Bronze Age in western Europe, which is generally agreed to begin around 3000 BCE. This finding extends our results from a direct investigation of aDNA in teeth from Iron Age burials near Vienna around 350 BCE and allow us to conclude that p.(Phe508del) was present in that region long before then. More specifically, in the Austrian families studied, the Estiage data revealed a mean tMCRA value of 3575 years ago, which converts to 1558 BCE (Middle Bronze Age) .
Perhaps most remarkably, the estimated ages of p.(Phe508del) in the three western European regions (France, Ireland, and Denmark) were similar with closely overlapping 95% CI values. This observation is also in line with previously documented spatial autocorrelograms expressing genetic and geographical distance for these populations . Such data provide more insight about the ancient origin of CF in our judgment—both when and where—and lead us to propose that CFTR p.(Phe508del) is derived from ancestors who lived in western Europe during the Bronze Age, as early as 2700 BCE, and that its relatively rapid dissemination occurred because of human migrations around the northwestern Atlantic trading routes  and then towards central and eastern Europe . Diffusion from northwestern to central Europe in approximately 1000 years is consistent with the prominent Bronze Age migrations evident in the archeological record [21, 22] and from genomic studies of aDNA . On the other hand, we are assuming a discrete origin of the principal CF-causing variant, but it is possible that p.(Phe508del) arose more than once or earlier, and then reached western Europe subsequently through Neolithic migrations.
[About Bell Beakers] (…) More specifically, their distinctive Bell Beaker pottery appeared and spread across western and central Europe beginning around 3000–2750 BCE and then disappeared between 2200 and 1800 BCE [22, 29]. Their migrations are linked to the advent of western and central European metallurgy, as they manufactured and traded metal goods, especially weapons, while traveling over long distances . Most relevant to our study is the evidence that they migrated in a direction and over a time period that fits well with the pattern of tMRCA data we found for the p.(Phe508del) variant. Olalde et al.  have shown that both migration and cultural transmission played a major role in diffusion of the “Beaker Complex” and led to a “profound demographic transformation” of Britain after 2400 BCE. Moreover, the cultural elements that unite the widely distributed Beaker folk are so obvious that some have considered them a distinct ethnicity of Bronze Age people .
From our results, we propose the novel concept that large scale, long term west-to-east migrations of the Bell Beaker Europeans [22, 28–30] during the Bronze Age, could explain the dissemination of p.(Phe508del) in Europe and its documented northwest-to-southeast gradient .In fact, our tMRCA data show a temporal gradient also.
As you can see from the references, they consulted with Barry Cunliffe (or people accepting his theory), who is obsessed with Bell Beakers expanding Celtic languages from the British Isles. He is like the British equivalent of Danish scholar Kristian Kristiansen, and his obsession with Corded Ware = Indo-European (and Germanic = CWC Denmark), immutable no matter what genetic results might show.
The funny thing is, the interpretation of the paper is probably right. From what we can see in the data, it is quite possible that the disease spread with expanding Bell Beakers…only it spread from the East group in Hungary, i.e. from east to west. The regional difference in TMRCA and apparent west—east cline would point to the different expansions of affected lineages in the corresponding regions, and not to an origin in the British Isles.
This paper focuses on the usefulness of the label ‘mixed languages’ as an analytical tool. Section 1 sketches the emergence of the biological paradigm in linguistics and its effect on the contemporary debate about mixed languages. Sections 2 and 3 discuss two processes that have been held responsible for the emergence of mixed languages, code switching and extreme borrowing. Section 4 compares these two mechanisms with the categories of change in Thomason & Kaufman (1988), while Section 5 offers some conclusions about the status of mixed languages as a special category.
Although the paper is a must read for language contact and language change (code-switching, borrowing, shifting), a good summary may save you some time if you are not interested in linguistics:
Speakers may either shift to a new language while retaining traces of their old language, or they may stick to their original language while borrowing from another language with which they come in touch (…)
[Bakker] distinguishes two types of communities in which mixing is found: isolated mixed marriage communities with (asymmetrical) bilingualism; and nomadic communities that shift to a dominant language, but retain a substantial part of their lexicon as a private or secret register, closely connected with the community’s identity. The history of these communities provides us with plausible scenarios to explain the idiosyncrasies of the speech pattern of the speakers belonging to them.
In what way, then, does it help to put both categories under one label of mixed languages? I believe Backus (2003: 263) is right when he suggests that the question of whether a certain set of features constitutes a mixed language is perhaps not a very interesting one. The question should not be whether given certain features a language may be categorized as mixed, but what the linguistic effects of different kinds of contact (trade, work, conquest, mixed marriages, colonization, marginalization, etc.) are, and to what extent these effects correlate with the type of contact. At no point is it necessary to posit a category of mixed languages. In fact, the myth of the mixed languages may have been perpetuated because of the relative weirdness of the initial cases, notably that of Michif, which represent phenomena so unique that it is understandable that some scholars came to believe that they could only be explained by special mechanisms. The position taken here is that if we focus on the speakers’ behavior, the phenomena in question become much more understandable. The crucial point is that languages do not mix, people do.
Recently there has been growing interest in characterising population structure in cultural data in the context of ongoing debates about the potential of cultural group selection as an evolutionary process. Here we use archaeological data for this purpose, which brings in a temporal as well as spatial dimension. We analyse two distinct material cultures (pottery and personal ornaments) from Neolithic Europe, in order to: a) determine whether archaeologically defined “cultures” exhibit marked discontinuities in space and time, supporting the existence of a population structure, or merely isolation-by-distance; and b) investigate the extent to which cultures can be conceived as structuring “cores” or as multiple and historically independent “packages”. Our results support the existence of a robust population structure comparable to previous studies on human culture, and show how the two material cultures exhibit profound differences in their spatial and temporal structuring, signalling different evolutionary trajectories.
Our results suggest distinct evolutionary histories in the spatial and temporal variation of personal ornament and pottery, with different rates of innovation, patterns of descent, and dynamics of diffusion. Ornament data do show statistically significant values of ΦST using pottery-defined population structures, but the magnitude is extremely small, and partial Mantel tests suggest that much of this pattern is explained by isolation by distance. These results are in line with a model
of culture represented by independent “packages” of multiple coherent units rather than one characterised by a distinct and fairly isolated “core” surrounded by a “periphery” of elements prone to crosscultural transmission. The alternative hypothesis is that one element was part of the “core” tradition, whilst the other was peripheral. This scenario is however less likely given that both elements are generally regarded as expression of local lines of transmission and/or signalling.
The robust support for a population structure in the pottery data shows that some degree of homophily must have biased the transmission process, but this bias was confined within the single “package”, rather than affecting other aspects of the material culture. In other words similarity (or dissimilarity) of pottery style was not influencing the transmission process of personal ornaments and vice-versa. If this was the case, we should have observed a stronger agreement between in the spatio-temporal distribution of the two datasets, a pattern we failed to observe. Personal ornaments are often seen as group-identity markers, but the fact that our study appears to indicate a stronger role for isolation by distance in accounting for variation in ornaments suggests that this assumption may not be valid, or alternatively that these groups cross-cut the archaeological cultures traditionally recognised. Thus,while our study has provided strong evidence of population structure affecting patterns of cultural interaction, in this case at least the distinct patterns observed point to a modular, ‘package’ model. It has also shown that we can identify population structuring from the evidence of the archaeological record without continuing to attempt the fruitless task of correlating its patterns with past ethnolinguistic units.
This logical description different cultural changes brings up a question obvious to many, and can be summed up by “does the arrival of (North-West Indo-European-speaking) East Bell Beakers mean the end of non-Indo-European cultures in Western and Northern Europe?” The answer is obviously – as in the rest of Europe – quite simply No. Many non-Indo-European groups must have survived the initial expansion of East Bell Beakers in many regions, as the pre-Roman situation (already quite simplified after the expansion of Celtic and Germanic) testifies.
“Resurgence” of local groups as seen in genomic data is the most direct connection with survival of previous non-IE cultures (and thus languages), but obviously not the only mechanism of language survival, since we can see founder effects – such as those seen in modern Basque speakers (mainly of R1b subclades), and in Ugro-Finnic speakers in north-east Europe (mainly of N subclades).
I am recently stumbling more and more often upon the concept of ‘Steppe people‘ by amateur geneticists, whether in Anthrogenica, in blogs and blog comments, or even in research papers, where people used to talk about ‘Yamnaya people’ or ‘Yamnaya folk’. As I said, I expected this since I questioned the concept of the ‘Yamnaya ancestral component‘, so I feel vindicated by this change.
However, whereas most will be using these names simply following the redeeming term “steppe admixture”, and thus refer to a Neolithic steppe population that shared a common admixture component (probably ca. 5000 BC), some will obviously go further and identify this component with Proto-Indo-European (like that, in general terms), since it is the logical sequence for those who consider the term “Indo-Europeans” as an umbrella for a certain ethnic proportion and a link with modern populations in stupid autochthonous continuity theories, where prehistoric language and culture are irrelevant.
Some people like to talk about how “Science” wins against Academia, especially when they try to defend this pseudo-subfield they are inventing and venerating on the go to characterize ancient populations, where new genomic methods are king, and the other fields involved are just noise they easily use or dismiss to support their own desires and preconceptions.
Too bad for them. The misuse of this new field might be popular today among certain amateur geneticists, but it will not stand the test of time, similar to how the initial hype around radiocarbon analysis (for Archaeology) or glottochronology (for Linguistics) eventually faded, and they became just another tool among traditional methods. In Science, time puts everything where it belongs.
Whether you like it or not, Indo-European (and Uralic) questions will be solved – as they have been for a long time now, there is nothing new under the sun – with Historical Linguistics first, then Prehistoric Archaeology, then Anthropology (models of migration, cultural diffusion, founder effects, etc.), and only then Genomics, which may (or may not) help solve certain controversial aspects, by supporting one or other anthropological model. Period.