This paper presents a computer-based method to estimate optimal migration routes of early human population groups by a combination of ecological niche analysis and least-cost path analysis. In the proposed method, niche probability is predicted by MaxEnt, an ecological niche model based on the maximum entropy theory. Location of known archaeological sites and environmental factors derived from palaeoterrain and palaeoclimate models, are input to the model to calculate the niche probability at each spatial pixel and weights of the environmental factors. The inverse of probability score is then used as an index of relative dispersal rate to accumulate the travel cost from a given origin. Based on this cumulative cost surface, least-cost paths from the origin to given destinations are visualised. This method was applied to the Initial Upper Palaeolithic population group (probably of modern humans) in Eurasia. The model identified three migration routes from the Levant to (1) Central Europe via Anatolia and Eastern Europe, (2) the Russian steppe via Caucasus Mountains, and (3) the Altai region via the southern coastal Iran and Afghanistan.
– There is a Yamna cultural-historical community (i.e. with a potential ethnolinguistic unity). Although many different inner groups can be distinguished (based on cultural, social, anthropological differences), one cannot divide the culture in distinct cultures.
– The Budzhak culture is likely the heir of Repin, which is compatible with its expansion westward. According to Klejn and Anthony (Usatovo), this region was connected to (and might have influenced) the Corded Ware culture. Therefore – that is my contribution, not theirs – a hidden community of R1a-M417 subclades (that a lot of people are eager to find) might have stemmed from there.
– Globular Amphorae and Corded Ware cultures are related, because GAC is actually not a uniform culture, but a ‘complex’ (i.e., in the same sense that Bell Beaker was not a culture, but a complex, as genetics has shown), and CWC is also a complex of cultures, as supported by Furholt. If that is true, the sampling of certain peoples classified as from Globular Amphorae – which some have rushed to cite as the end of the GAC-CWC connection might not be the last word, and Kristiansen’s model of long-lasting GAC-CWC connection may still be open.
Aspects I disagree with
– There is no migration, but long-lasting contacts that show up in genetics, since the Mesolithic-Neolithic transition. In my opinion, the expansion of admixture + haplogroup reduction and expansion depict clear migratory movements (although, obviously, without cultural identification no speculative ethnolinguistic grouping can be proposed). That much is obvious from Genomics, and if we are not going to accept the most basic findings as proof in favour of certain anthropological models, then Archaeology will not benefit at all from genetic studies.
– Because this is the Russian school of thought, when they talk about Proto-Indo-European they refer to a homeland dating to the Mesolithic-Neolithic transition, and therefore cultural-historical communities after that (and long-lasting contacts) refer to potential continuations of Proto-Indo-European. Following common language guesstimates, though, there is no reason to date the split of Anatolian from a common Indo-Hittite before ca- 4500 BC, since there is no reason to date a Late Proto-Indo-European beyond 4000-3000 BC, apart from controversial glottochronological studies…
New human aDNA studies have once again brought to the forefront the role of mobility and migration in shaping social phenomena in European prehistory, processes that recent theoretical frameworks in archaeology have downplayed as an outdated explanatory notion linked to traditional culture history. While these new genetic data have provided new insights into the population history of prehistoric Europe, they are frequently interpreted and presented in a manner that recalls aspects of traditional culture-historical archaeology that were rightly criticized through the 1970s to the 1990s. They include the idea that shared material culture indicates shared participation in the same social group, or culture, and that these cultures constitute one-dimensional, homogeneous, and clearly bounded social entities. Since the new aDNA data are used to create vivid narratives describing ‘massive migrations’, the so-called cultural groups are once again likened to human populations and in turn revitalized as external drivers for socio-cultural change. Here, I argue for a more nuanced consideration of molecular data that more explicitly incorporates anthropologically informed mobility and migration models.
I was copying and pasting whole excerpts to post them here, but I think it is best to read the full paper.
It is a great summary of potential flaws of the current reasoning in genetic papers.
It should be a must-read for any serious geneticist involved in discussions on migrations, especially regarding archaeology in Indo-European studies.
#EDIT (30 DEC 2017): Check out the interesting article by Bruce G. Trigger, referenced by John Hawks, about the question of descriptive vs. theoretical archaeologist vs. ethnologist/anthropologist from the 1950s to the 1980s. Interesting to see how today the new playboys in Academia, geneticists, are playing the archaeologist playing the ethnologist playing the linguist in Indo-European questions, and how we are living a historical debate on essential questions for the future of all these disciplines.
Summarizing spatial patterns in human genetic diversity to understand population history has been a persistent goal for human geneticists. Here, we use a recently developed spatially explicit method to estimate “effective migration” surfaces to visualize how human genetic diversity is geographically structured (the EEMS method). The resulting surfaces are “rugged”, which indicates the relationship between genetic and geographic distance is heterogenous and distorted as a rule. Most prominently, topographic and marine features regularly align with increased genetic differentiation (e.g. the Sahara desert, Mediterranean Sea or Himalaya at large scales; the Adriatic, inter-island straits in near Oceania at smaller scales). We also see traces of historical migrations and boundaries of language families. These results provide visualizations of human genetic diversity that reveal local patterns of differentiation in detail and emphasize that while genetic similarity generally decays with geographic distance, there have regularly been factors that subtly distort the underlying relationship across space observed today. The fine-scale population structure depicted here is relevant to understanding complex processes of human population history and may provide insights for geographic patterning in rare variants and heritable disease risk.
Among ‘effective migration surfaces‘ (or potential past migration routes), the Pontic-Caspian steppe and its most direct connection with the Carpathian basin, the Danubian plains, appear maybe paradoxically as a constant ‘trough’ (below average migration rate) in all maps.
It most likely (at least partially) represents a rather recent historical barrier to admixture, involving successive Byzantine, South Slavic, and Ottoman spheres of influence positioned against Balto-Slavic societies of Eastern Europe.
Featured image, from the article: “Large-scale patterns of population structure. a: EEMS posterior mean effective migration surface for Afro-Eurasia (AEA) panel. ‘X’ marks locations of samples excluded as displaced or recently admixed. ‘H marks locations of excluded hunter-gatherer populations. Regions and features discussed in the main text are labeled. Approximate locations of troughs are annotated with dashed lines (see Extended Data Figure 4). b: PCA plot of AEA panel: Individuals are displayed as grey dots, colored dots reflect median of sample locations; with colors reflecting geography and matching with the EEMS plot. Locations displayed in the EEMS plot reflect the position of populations after alignment to grid vertices used in the model (see methods).”
We examined tau haplotype frequencies in two different ethnical groups from the Basque Country (BC): Roma people and residents of European ancestry (general population). In addition, we analyzed the spatial distribution of tau haplotypes in Eurasian populations to explore the genetic affinities of the Romani groups living in Europe in a broader scope. The 17q21.31 genomic region was characterized through the genotyping of two diagnostic single nucleotide polymorphisms, SNPs (rs10514879 and rs199451), which allow the identification of H1 and H2 haplotypes. A significant heterozygous deficit was detected in the Romani for rs10514879. The H2 haplotype frequency proved to be more than twice in the BC general population (0.283) than in the Roma people (0.127). In contrast, H2 frequency proved to be very similar between Basque and Hungarian Romani, and similar to the H2 frequencies found in northwestern India and Pakistan as well. Several statistical analyses unveiled genetic structuring for the MAPT diversity, mirrored in a significant association between geography and genetic distances, with an upward trend of H2 haplotype frequencies from Asia to Europe. Yet, Roma samples did not fit into this general spatial patterning because of their discrepancy between geographical position and H2 frequency. Despite the long spatial coexistence in the Basque region between the residents of European ancestry and the Roma, the latter have preserved their Asian genetic ancestry. Bearing in mind the lack of geographical barriers between both ethnical groups, these findings support the notion that sociocultural mores might promote assortative matings in human populations.
The Neolithic transition in west Eurasia occurred in two main steps: the gradual development of sedentism and plant cultivation in the Near East and the subsequent spread of Neolithic cultures into the Aegean and across Europe after 7000 cal BCE. Here, we use published ancient genomes to investigate gene flow events in west Eurasia during the Neolithic transition. We confirm that the Early Neolithic central Anatolians in the ninth millennium BCE were probably descendants of local hunter–gatherers, rather than immigrants from the Levant or Iran. We further study the emergence of post-7000 cal BCE north Aegean Neolithic communities. Although Aegean farmers have frequently been assumed to be colonists originating from either central Anatolia or from the Levant, our findings raise alternative possibilities: north Aegean Neolithic populations may have been the product of multiple westward migrations, including south Anatolian emigrants, or they may have been descendants of local Aegean Mesolithic groups who adopted farming. These scenarios are consistent with the diversity of material cultures among Aegean Neolithic communities and the inheritance of local forager know-how. The demographic and cultural dynamics behind the earliest spread of Neolithic culture in the Aegean could therefore be distinct from the subsequent Neolithization of mainland Europe.
The analysis of the paper highlights two points regarding the process of Neolithisation in the Aegean, which is essential to ascertain the impact of later Indo-European migrations of Proto-Anatolian and Proto-Greek and other Palaeo-Balkan speakers(texts partially taken verbatim from the paper):
The observation that the two central Anatolian populations cluster together to the exclusion of Neolithic populations of south Levant or of Iran restates the conclusion that farming in central Anatolia in the PPN was established by local groups instead of immigrants, which is consistent with the described cultural continuity between central Anatolian Epipalaeolithic and Aceramic communities. This reiterates the earlier conclusion that the early Neolithisation in the primary zone was largely a process of cultural interaction instead of gene flow.
The realisation that there are still two possibilities regarding the question of whether Aegean Neolithisation (post-7000 cal BC) involved similar acculturation processes, or was driven by migration similar to Neolithisation in mainland Europe — a long-standing debate in Archaeology:
Migration from Anatolia to the Aegean: the Aegean Neolithisation must have involved replacement of a local, WHG-related Mesolithic population by incoming easterners. Central Anatolia or south Anatolia / north Levant (of which there is no data) are potential origins of the components observed. Notably, the north Aegeans – Revenia (ca. 6438-6264 BC) and Barcın (ca. 6500-6200 BC) – show higher diversity than the central Anatolians, and the population size of Aegeans was larger than that of central Anatolians. The lack of WHG in later samples indicates that they must have been fully replaced by the eastern migrant farmers.
Adoption of Neolithic elements by local foragers: Alternatively, the Aegean coast Mesolithic populations may have been part of the Anatolian-related gene pool that occupied the Aegean seaboard during the Early Holocene, in an “out-of-the-Aegean hypothesis. Following the LGM, Aegean emigrants would have dispersed into central Anatolia and established populations that eventually gave rise to the local Epipalaeolithic and later Neolithic communities, in line with the earliest direct evidence for human presence in central Anatolia ca 14 000 cal BCE
On the archaeological evidence (excerpt):
Instead of a single-sourced colonization process, the Aegean Neolithization may thus have flourished upon already existing coastal and interior interaction networks connecting Aegean foragers with the Levantine and central Anatolian PPN populations, and involved multiple cultural interaction events from its early steps onward [16,20,64,74]. This wide diversity of cultural sources and the potential role of local populations in Neolithic development may set apart Aegean Neolithization from that in mainland Europe. While Mesolithic Aegean genetic data are awaited to fully resolve this issue, researchers should be aware of the possibility that the initial emergence of the Neolithic elements in the Aegean, at least in the north Aegean, involved cultural and demographic dynamics different than those in European Neolithization.
Featured image, from the article: “Summary of the data analyzed in this study. (a) Map of west Eurasia showing the geographical locations and (b) timeline showing the time period (years BCE) of ancient individuals investigated in the study. Blue circles: individuals from pre-Neolithic context; red triangles: individuals from Neolithic contexts”.