Mitogenomes show likely origin of elevated steppe ancestry in neighbouring Corded Ware groups

west-yamna-corded-ware

Open Access Mitochondrial genomes reveal an east to west cline of steppe ancestry in Corded Ware populations, by Juras et al., Scientific Reports (2018) 8:11603.

Interesting excerpts (emphasis mine, references have been deleted for clarity):

Ancient DNA was extracted from the Corded Ware culture individuals excavated in southeastern Poland (N = 12) and Moravia (N = 3). Late Eneolithic (N = 5) and Bronze Age human remains (N = 25) originated from western Ukraine and came from the Yampil barrow cemetery complex located in the north–western region of the Black Sea. Bronze Age individuals were associated with different archaeological cultures, including Yamnaya (N = 14), Catacomb (N = 2), Babyno (N = 4) and Noua (N = 5).

The PCA results described 50.62% of the variability and were combined with the k-means clustering (with the k value of 5 as the best representation of the data, at the average silhouette of 0.2608). Based on these results individuals associated with the western and eastern Yamnaya horizon (YAE and YAW in Fig. 2) were grouped within a cluster consisting of populations from central Eurasia and Europe (blue cluster) including people associated with eastern Corded Ware culture (CWPlM) and Baltic Corded Ware culture (CWBal). This cluster did not contain any populations linked with early Neolithic farmers (red), or hunter-gatherers (green and yellow). On the other hand, k-means clustering linked the western Corded Ware culture-associated population (CWW) with Near East and Neolithic farmer ancestry groups from western and central Europe.

pca-cwc-yamna
Modified image, from the paper. PCA based on mitochondrial DNA haplogroup frequencies with k-means clustering. The two principal components explained 50.62% of the total variance. Loading vectors, representing mitochondrial haplogroup contributions, are highlighted as grey arrows. Populations are grouped into four clusters according to k-means. Population abbreviations are as follows: BABA – Bronze Age Balkans; CAT – Catacomb Culture; CWPlM – Corded Ware Culture from Poland and Moravia; CWBal – Baltic Corded Ware Culture; IAK – Iron Age Kazakchstan; IASI – Iron Age Syberia – Aldy Bel Culture; SCA – Scytho-Siberian Pazyryk (Altai); SCR – Rostov-Scythians, Samara; SCU – Scythians from Moldova and Ukraine; TAG – Tagar Culture; GAC – Globular Amphora Culture; YAW – western Yamnaya horizon population from Ukraine and Bulgaria; YAE – eastern Yamnaya horizon population; BAC – Baalberge Culture; BANE – Bronze Age Near East; BEC – Bernburg Culture; CHAHu – Chalcolithic Hungary; CWW – Corded Ware Culture west; CHABA – Chalcolitic Balkans; EBAG – Early Bronze Age Germany; FBC – Funnel Beaker Culture; IAG – Iron Age Germany; MNG – Middle Neolithic Germany; LBK – Linear Pottery Culture; LDN – Late Danubian Neolithic; MIC – Minoans; NEBA – Neolithic Balkans; PPNE – Pre-Pottery Near East; SCG – Schöningen group; SMC – Salzmünde Culture; AND – Andronovo Culture; BASI – Bronze Age Siberia; PWC – Pitted Ware Culture; HGE – eastern hunter-gatherers; NEUk- Neolithic Ukraine; HGS – southern hunter-gatherers; HGBal – Baltic hunter-gatheres; HGC – central huther-gatherers.

Pairwise mtDNA-based FST values, visualized on MDS using the raw non-linearized FST (stress value = 0.099) (Fig. 4), also supported the PCA results and indicated that western and eastern Yamnaya horizon groups (YAW and YAE) were closer to people associated with the eastern Corded Ware culture (CWPlM) (FST = 0.00; FST = 0.01, respectively; both p > 0.05) and Baltic Corded Ware culture (CWBal) (FST = 0.00; FST = 0.00, respectively; both p > 0.05), than to populations associated with the western Corded Ware culture (CWW) (FST = 0.047 and FST = 0.059, respectively; both statistically significant p < 0.05). Western and eastern Yamnaya horizon groups also showed close genetic affinity to the Iron Age western Scythians (SCU) (FST = 0.0022 and FST = 0.006, respectively, both p > 0.05). The most distant populations to the Yamnaya horizon groups were western hunter-gatherers (HGW) (FST = 0.23 and FST = 0.15, p < 0.001).The FST-based MDS reflected the general European population history in the post-LGM period as the three highest FST scores were detected between western hunter-gatherers (HGW) and people associated with Linear Pottery culture (LBK) (FST = 0.33, p < 0.001), between eastern hunter-gatherers (HGE) and Baltic hunter-gatherers (HGBal) (FST = 0.35, p < 0.05), and between western (HGW) and eastern hunter-gatherers (HGE) (FST = 0.36, p < 0.05). The Yamnaya horizon groups (YAE and YAW) were placed centrally between northern hunter-gatherers (HGN) and Neolithic farmers (LDN), in direct proximity to the Bronze and Iron Age populations from Eastern Europe (SCU, BARu, SRU) and close to individuals associated with eastern and Baltic Corded Ware culture.

yamna-corded-ware-pca
Modified image, from the paper. In circles, relevant European groups for the question of ‘steppe ancestry’. MDS plot based on FST values calculated from mitochondrial genomes. Population abbreviations: BBC – Bell Beaker Culture; BAHu – Bronze Age Hungary; BARu – Bronze Age Russia; CWPlM – Corded Ware Culture from Poland and Moravia; CWW – western Corded Ware Culture; CWBal – Baltic Corded Ware Culture; EBAG – Early Bronze Age Germany; GAC – Globular Amphora Culture; HGE – eastern hunter-gatherers; HGN – northern hunter-gatherers; HGW – western hunter-gatherers; HGBal – Baltic hunter-gatherers; LBK – Linear Pottery Culture; LDN – Late Danubian Neolithic; MNE – Middle Neolithic; NENE – Near Eastern Neolithic; SCU – Scythians from Moldova and Ukraine; SRU – Rostov-Scythians, Samara.

Among the analyzed samples, we identified two Catacomb culture-associated individuals (poz220 and poz221) belonging to hg X4. They are the first ancient individuals assigned to this particular lineage. Haplogroup X4 is rare among present day populations and has been found only in one individual each from Central Europe, Balkans, Anatolia and Armenia.

Moreover, we have reported mtDNA haplotypes that might be associated with the migration from the steppe and point to genetic continuity in the north Pontic region from Bronze Age until the Iron Age. These haplotypes were assigned to hgs U5, U4, U2 and W3. MtDNA hgs U5a and U4, identified in this study among Yamnaya, Late Eneolithic and Corded Ware culture-associated individuals, have previously been found in high frequencies among northern and eastern hunter-gatherers. Moreover, they appeared in the north Pontic region in populations associated with Mesolithic (hg U5a), Eneolithic (Post-Stog) (hg U4), Yamnaya (hgs U5, U5a), Catacomb (hgs U5 and U5a) and Iron Age Scythians (hg U5a), suggesting genetic continuity of these particular mtDNA lineages in the Pontic region from, at least, the Bronze Age. Hgs U5a and U4-carrying populations were also present in the eastern steppe, along with individuals from the Yamnaya culture from Samara region, the Srubnaya and the Andronovo from Russia. Interestingly, hg U4c1 found in the Yamnaya individual (poz224) has so-far been found only in two Bell Beaker- associated individuals and one Late Bronze Age individual from Armenia, which might suggest a steppe origin for hg U4c1. A steppe origin can possibly also be assigned to hg U4a2f, found in one individual (poz282) but not reported in any other ancient populations to date, and to U5a1- the ancestral lineage of U5a1b, reported for individual poz232, which was identified not only in Corded Ware culture-associated population from central and eastern Europe, but also in representatives of Catacomb culture from the north Pontic region, Yamnaya from Bulgaria and Russia, Srubnaya and Andronovo-associated groups. Hg U2e, reported for Late Eneolithic individual (poz090), was also identified in western Corded Ware culture-associated individual and in succeeding Sintashta, Potapovka and Andronovo groups, suggesting possible genetic continuity of U2e1 in the western part of the north Pontic region.

Hgs W3a1 and W3a1a, found in two Yamnaya individuals from this study (poz208 and poz222), were also identified in Yamnaya-associated individuals from the Russia Samara region and later in Únětice and Bell Beaker groups from Germany, supporting the idea of an eastern European steppe origin of these haplotypes and their contribution to the Yamnaya migration toward the central Europe. The W3a1 lineage was not identified in Neolithic times and, thus, we assume that it appeared in the steppe region for the first time during the Bronze Age. Notably, hgs W1 and W5, which predate the Bronze Age in Europe, were found only in individuals associated with the early Neolithic farmers from Starčevo in Hungary (hg W5), early Neolithic farmers from Anatolia (hg W1-T119C), and from the Schöningen group (hg W1c) and Globular Amphora culture from Poland (hg W5).

west-yamna-west-corded-ware

Some comments

The most recent radiocarbon dates show that Early Yamna expanded to the west with Repin settlers of the Lower Don ca. 3350/3300 BC. At the end of the 4th millennium, then, these settlers dominated over groups whose population had in turn also elevated ‘steppe ancestry’ (at least from ca. 4000 BC, as shown by Ukraine Eneolithic samples from the forest-zone), and probably replaced the male population completely, as evidenced by other Yamna and Poltavka, and later Bell Beaker, Catacomb, and Sintashta samples.

The ‘second wave’ of expansion of Yamna settlers to the west, into east-central European steppes, began probably ca. 3100/3000 BC, and – based on material culture – stemmed mainly from the North Pontic area. The Yampil Barrow Complex on the Dnieper (which I recently wrote about) seems to be part of one of the groups of western Yamna migrants: those who migrated westward from the left bank of the Dniester to the west into the Prut-Siret region, and north along the Prut.

This region is the key for population movements that gave rise to the Corded Ware culture (see another recent post on Corded Ware origins). It is quite likely that we will see a dance of late Trypillia / Usatovo, GAC, (Proto-)Corded Ware, and Yamna samples in this area. Judging by the clear-cut Y-DNA bottlenecks we are seeing in Neolithic populations, especially among steppe pastoralists, the difference between groups in recovered ancient samples will not only be clear from their culture, but also from their male lineages.

Based on the number of burials studied from the different settlement regions for West Yamna migrants, the Prut-Siret group was one of the smallest new Yamna ‘provinces’ in south-eastern Europe, and was probably overrun early, although – since kurgan findings continued into the Catacomb culture in the Yampil complex – the Dnieper region was well-enough connected to the core North Pontic area to be kept into its retreating territory by 2500 BC, as was the Danube delta, in contrast with other east-central European areas.

steppe-chalcolithic-migrations
Steppe-related migrations ca. 3100-2600 BC with tentative linguistic identification.

Taking into account that the earliest Corded Ware burials are from ca. 2900 BC (in the Single Grave culture), and that the earliest A-horizon pottery expanded from Lesser Poland (a syncretic pottery based on the previous GAC-type) a century later, it is likely that what this paper shows for Corded Ware in eastern Europe and the Baltic is what I have suggested many times (see here, or here) as the most likely reason for elevated steppe ancestry (and close PCA cluster) of the Baltic LN ‘outliers’: the exogamy of Corded Ware groups with females from Yamna or a North Pontic steppe culture with similar ancestry.

If Proto-Corded Ware populations of the North Pontic region did not have an identical “steppe ancestry” to these eastern CW groups already during the Eneolithic (which is the other possibility), I might be right in their more recent exogamy, and this could be seen in this study by the close cluster of east Corded Ware (especially Baltic) mtDNA to GAC and Yamna West groups, and distant from previous hunter-gatherer populations of the area, which suggests that expanding males from the Volhynia/Podolia region practiced exogamy mainly with southern groups.

I think this is probably related to demographic pressure imposed on other populations by the explosive expansion of pastoralists with their new subsistence economy (part of the “Secondary Products Revolution”), which the hunter-gatherer and farmer population of Europe could not keep up with (as seen later in the admixture of expanding East Bell Beakers), although studies on European prehistoric demography are scarce and too general to tell us anything relevant for this precise period and region.

Related

Sredni Stog, Proto-Corded Ware, and their “steppe admixture”

steppe-eneolithic-migrations

Once the haplogroups of the announced West Yamna and Yamna settlers in Hungary and Khvalynsk from Ekaterinovka appear, it is to be expected that there won’t be much discussion on the Y-DNA bottlenecks that affected Khvalynsk – Yamna migrations.

So let’s cut to the chase and see where Corded Ware peoples (mainly of R1a-Z645 subclades) got their so-called “steppe admixture” different from that of Yamna. Because, as you might have realized by now, Sredni Stog – and consequently Corded Ware – remains nowadays an undefined (archaeological) mess.

Rassamakin explains it quite well, in the chapter Eneolithic of the Black Sea Steppe; In Levine M., Rassamakin Yu., Kislenko A. and Tatarintseva N., 1999. Late Prehistoric Exploitation of the Eurasian Steppe. McDonald Institute Monographs, University of Cambridge.

NOTE. These are only certain relevant excerpts. The whole chapter is worth a thorough read, whatever position you hold regarding steppe expansions. In fact, he supports the Skelya cultural (macro-)group instead of Khvalynsk-Novodanilovka vs. Sredni Stog, he does not believe in significant expansions from the east (but in local movements and a ‘general evolution’ of Pontic-Caspian steppe cultures to Early Yamna), and offers e.g. the presence of copper and trade from the west (and its poor presence in the east) as an example of the importance of the North Pontic area vis-à-vis Khvalynsk/Repin. Not an interested party in supporting Gimbutas or Anthony, then, if you fear that.

Cultural groups in the North Pontic area

Telegin divided the Sredny Stog culture into three local variants – the Dnepr Culture variant, the Oskol-Donets (Aleksandriya) Culture variant, and the Lower Don (Konstantinovka) Culture variant. He elaborated a periodization based on the evolution of decorative motifs in the pottery assemblages.

At first, the internal contradictions of the Sredny Stog culture were not accorded particular prominence, despite clear intimations of problems when, for example, sites like the settlement of Konstantinovka on the Lower Don, was identified as actually belonging to another, independent culture (Kiyashko 1974). The first real blow to the integrity of the Sredny Stog culture was dealt by Telegin himself, when he removed five Novodanilovka-type sites, and accorded them the status of an independent cultural phenomenon (Telegin 1985a). Until that point, sites of this type had were customarily considered to be within the framework of the late group of Sredny Stog cemeteries, despite having been for long regarded by some as representative of an earlier, independent cultural group (Movsha & Chebotarenko 1969; Zbenovich 1973, 74-5; Gimbutas, Merpert and Danilenko passim). Indeed, it was unclear why these cemeteries had initially been assigned to the Late, rather than the Early, Sredny Stog culture. Now these sites were mechanically stripped out of the one system, but their place in the new system was not clearly defined.

rassamakin-skelya-culture
Rassamakin (1999) concept of cultural development of burial rituals in the North Pontic steppe.

Thus a paradox arose. Sites that had served to a considerable extent as the initial basis for the Sredny Stog culture, for the elaboration of its periodization and chronology, were now accepted as forming the core of an essentially different culture. Because of this, by the mid 1980s, both the Sredny Stog culture and the Eneolithic systematization as a whole were becoming rather amorphous. Essentially, the Sredny Stog culture was associated in the minds of many researchers solely with the settlement site at Dereivka, while they had only a confused and indistinct idea of the nature of early Sredny Stog sites. (…) Ultimately a situation developed where all attempts to view new evidence, new local groups, or even cultures through the prism of the Sredny Stog culture were futile, since researchers were unclear about of the essence of the culture itself, and often qualified themselves in footnotes with references to ‘preCorded Ware’ or ‘Corded Ware’ stages, or by relating their observations back directly to the specific sites of Sredny Stog II or Dereivka.

Thus, in the Middle Eneolithic, a number of independent cultures (Kvityana, Repin, Konstantinovka, and, to some degree, Dereivka, Cernavoda and Lower Mikhailovka) emerged in the region that had in the Early Eneolithic been occupied by the Skelya culture, either as lineal successors to this culture or under its influence. But the principal stimuli in this period were the Tripolye tribes, direct imports from whom reach the southern zone of the Dnepr left bank.

It is apparent that, for all their conceptual differences, if we remove Danilenko’s subdivisions, Telegin’s and Danilenko’s models are identical in terms of site periodization and sequence: first Kvityana, then Sredny Stog II, and finally Dereivka.

The North Pontic area in the Eneolithic (4000-3500 BC)

kvityana-dereivka-repin-trypolie-maykop
The Kvityana and Dereivka cultures in relation to other sites: 1) Molyukhov Bugor (settlement); 2) Dereivka (settlement); 3) Aleksandriya (settlement); 4) Minevsky Yar (settlement); 5) Khutor Repin (settlement).

Tripolye influence is seen most clearly in the development of the Lower Mikhailovka culture and a new burial rite which spread as far as the Molochnaya. Changes are apparent in kurgan architecture; that is, in the construction of stone chambers, sanctuaries comprising upright elements, and ring-shaped ditches (Rassamakin 1990; 1993; 1994; Pleshivenko & Rassamakin 1994 ). Lower Mikhailovka sites in the northwestern Black Sea coast region are known by a whole series of different designations, one of which, as I have already noted above, is ‘the Bessarabian variant of the Cernavoda I culture’ (Manzura 1993).

The formation of the Kvityana culture should be considered both in the context of the development of the Lower Mikhailovka culture, and in terms of the influence of the Sredny Stog II pottery assemblage. The first is manifested in the development of the kurgan ritual itself, with such structural elements as cromlechs, orthostats and stone cists. These are most apparent to the south, in the zone of contact with the Lower Mikhailovka culture. The second is apparent in the similarity between Kvityana pottery and Sredny Stog II pottery, notably in a number of shared compositional and technical elements, despite the fact that the shapes, techniques and style are all quite different.

As a whole, the Kvityana culture is notably conservative and archaic in appearance; this is manifest both in the preservation of a burial rite involving a supine position, and in the appearance of the pottery which, on the basis of the absence of corded or caterpillar track decoration, was until recently considered the earliest Sredny Stog ware.

(…) we still lack sufficient evidence to trace in detail the path by which the Kvityana culture spread from the Dnepr into the Dnestr-Danube region. The southern steppe route is excluded, but Kvityana sites are recorded on the Southern Bug, in the Dnestr region, and even along the forest-steppe boundary on the Prut Gudging by the numerous excavations of kurgans in this belt. This route in some respects repeats that along which the Skelya elite groups moved. Southward movement along the Southern Bug and its tributaries into the steppe zone is indicated only by isolated sites, the number of which is far smaller than in the Dnestr-Danube region, despite the intensive excavation of kurgans in this region. Evidence for Kvityana penetration into the northwestern Black Sea coast is provided by the appearance in Usatovo assemblages of typical Kvityana figural tubular bone beads, with diagnostic lateral notches on the sides (Malyukevich & Petrenko 1993).

kvityana-cucuteni-tripolye-expansions
Expansions of Kvityana and Trypillia cultures. Rassamakin (1999)

[The Dereivka] culture is currently only known only from settlement material, notably from sites in the Dnepr region (Dereivka and Molyukhov Bugor), but also from typologically distinctive pottery in the Eneolithic layer of the settlement of Aleksandriya on the Oskol. Dereivka culture pottery has also been recorded at a number of locations in the forest-steppe Dnepr region and the Seversky Donets, at Tetyanchino, Kamennye Pataki, and Minevsky Yar. The ceramic assemblage is well-defined and easily recognizable: vessels consistently display a weak profile and slightly elongated proportions, with high, straight mouths, evenly cut off at the rim, and conical bases (Fig. 3.23). The Dereivka culture occupies the southern part of the forest-steppe region and is bounded to the south by the Kvityana culture.

Telegin rightly noted that Dereivka and Kvityana pottery bore some resemblance to one another. Several fragments of the latter were found in the Dereivka assemblage, and provide evidence for the contemporaneous existence of the two cultures. The Molyukhov Bugor pottery assemblage stands out in terms of a prevalence of pottery with corded decoration, which only occurs in insignificant amounts at Dereivka and Aleksandriya. However, artefactual analysis has not produced any clear guidance for a chronological organization of these sites, as was postulated by Telegin.

sredni-stog-yamnaya
Rassamakin’s (1999) periodization of the North Pontic cultures

Late Phase and Final Eneolithic (3500-3000 BC)

In the Dnestr region, southward pressure from Tripolye led to the formation of, firstly, Vykhvatinsk-type sites, and then, in the steppe zone, Usatovo-type sites, which had undoubtedly absorbed some features of the Lower Mikhailovka culture. In the Prut and Middle Dnestr regions, sites of the Gordineşti (Kasperovkao) types are formed (these correspond, in the Romanian Prut region and on the Siret, to sites of the Horodiştea-Erbiceni type, and on the Lower Danube to the Cernavoda III culture: Morintz & Roman 1968; Dinu 1980; 1987). Movsha considers that sites of this type (Kasperovkao in her terminology) also occur in the Southern Bug region.

Sofievka-type sites emerge in the forest-steppes of the Middle Dnepr. A number of researchers (Zbenovich, Dergachev, and Sorokin), taking account of the change in the Tripolye culture at stage C2, propose a special division, considering sites of this period alone as ‘Late Tripolye’. In their view (with which I agree), stage Cl in culture-historical terms still corresponds to ‘Middle Tripolye’.

(…) existing evidence allows us to put forward the following scheme (Fig. 3.49:2). To the east of the Usatovo sites, from the lower reaches of the Southern Bug to the Azov region, encroaching on the Crimean steppes, the Lower Mikhailovka culture remains intact. To the north, upstream along the Dnepr and its tributaries, the Kvityana culture survives in its initial core zone. Between the Southern Bug and the Dnepr, in the contact zone between the three cultures (Tripolye, Lower Mikhailovka and Kvityana) the Dnepr-Bug group of sites emerges, displaying mixed features (Nikolova & Rassamakin 1985; Rassamakin 1988) Tripolye influence on the Dereivka culture appears to increase, as manifested in the appearance of late cultural elements (corded decoration, plastic art, bowls). The fate of the Pivikha culture is unclear. On the Lower Don, the late phase of the Konstantinovka culture (corresponding to the settlements of Konstantinovka and Razdorskoe I: Level 7) continued.

The final stage

The final stage of this period is characterized by two waves of migration, which properly speaking conclude the development of the Eneolithic.(…)

The first migration is connected with the breakdown of that system of Late Tripolye forest-steppe sites of the Prut-Dnestr and Southern Bug regions, dealt with by Movsha within the framework of the Kasperovo local group (and termed Gordineşti by others such as Dergachev, Manzura, and Petrenko). Almost all researchers into the Tripolye culture note the widespread occurrence of diagnostic elements of this group in the south, in the zone of the Usatovo sites and, in the east and southeast, towards the Dnepr and its left bank (Movsha 1984; 1990; 1993; Subbotin & Petrenko 1986; Manzura 1990a). (…)

The migrational wave that left Zhivotilovo-Volchanskoe-type burials in the steppe also linked up the forest-steppe Bug, Dnestr, and Prut regions with the Lower Don region, and, possibly with the North Caucasus, where the late stage of the Maikop culture (the Novosvobodnaya sites) continued. The identical rites of the Maikop culture and Zhivotilovo-Volchanskoe sites makes it difficult to establish the direction of migration, or which was the active side in the process. A number of researchers have given precedence to the Maikop culture. But the spread of the Tripolye assemblage unambiguously indicates the active involvement of the Tripolye tribes.

north-pontic-kvityana-dereivka
The system of the latest Eneolithic Pointic cultures and the sites of the Zhivotilovo-Volchanskoe type: 1) Volchanskoe; 2) Zhivotilovka; 3) Vishnevatoe; 4) Koisug

The second migration, at the very end of the Eneolithic, is connected with the spread of the Repin culture (in its second phase) from the Middle Don. Sinyuk defined three main directions: north, to the Upper Don; southwest, into the Dnepr region; and south, to the Lower Don and the Lower Volga. Trifonov considers this broad expansion of the Repin culture to be colonization (Trifonov 1996). The Repin culture level at Razdorskoe I (Razdorskoe I: Level 8) overlies the Konstantinovka levels (Levels 6 and 7), signalling that the Konstantinovka culture had apparently ceased to exist (Kiyashko 1994, 80). It seems that the expansion of the Repin culture is also associated with a reduction in the territorial extent of the Kvityana and Dereivka cultures. Repin burial assemblages, settlements and temporary camps appear in the Seversky Donets basin and in the Eastern Azov region (at Trekhizbenka, Kapitanovo, Aleksandriya, and Razdolnoe). The same complexes are also widely distributed towards the Dnepr (Marina 1992). The most striking western manifestation of Repin elements is seen in the upper horizon of the middle level of the Mikhailovka settlement (Lagodovska et al. 1962, 39-46).

Khvalynsk-Yamna and Sredni Stog-Corded Ware

We already know that Ukraine Eneolithic samples showed steppe ancestry and had apparently began a process of convergence coinciding with (or after) the first Khvalynsk-related migrations. It is unclear what had happened before (i.e. how much “CHG ancestry” was absorbed by Ukraine Neolithic groups in their transition to the Eneolithic before ca. 4500 BC), although in principle we can assume that all Caucasus-related admixture received by North Pontic cultures ca. 4500-4000 BC was mediated by westward movements from Khvalynsk-related peoples.

PCA-caucasus-lola-ane-chg
Image modified from Wang et al. (2018). Samples projected in PCA of 84 modern-day West Eurasian populations (open symbols). Previously known clusters have been marked and referenced. An EHG and a Caucasus ‘clouds’ have been drawn, leaving Pontic-Caspian steppe and derived groups between them.See the original file here.

Contacts with (and later absorption of) Khvalynsk-Novodanilovka-related migrants, as well as heir cultures, like those in the steppe adjacent to the Black Sea coast, and also direct contacts with Caucasus-related populations through Zhivotilovo-Volchanskoe can justify a greater contribution of CHG ancestry ca. 4000-3500 BC. Close contacts with Cucuteni-Trypillia (through Mikhailovka and maybe Kvityana, possibly with WHG and CHG admixture related to Khvalynsk-Novodanilovka) and GAC peoples to the north are the obvious source of further similarities with Yamna. Distinct similarities, that is, if we take into account the different sources and timing of such ancestral components, and Y-chromosome bottlenecks…

Therefore, after a process of convergence ca. 4500-4000 BC, and potentially more contacts with late Eneolithic North Pontic steppe cultures ca. 4000-3500 BC, Proto-Corded Ware peoples must have finally spread from the northernmost (forest-steppe) areas previously occupied by Dereivka, Pivikha, or Sofievka groups from ca. 3300 BC onwards – a date roughly coincident with the expansion of late Khvalynsk/Repin to the west developing the Early Yamna culture, with which it likely entered in contact (hence potentially a source for further admixture convergence ca. 3500-3000 BC).

Only later happened the great migration ca. 3000-2800 BC of Classical Corded Ware culture migrants, at the same time as Early Yamna migrants expanded to the west, and some groups also to the north along the Prut (possibly directly connected to the admixture found in the two Baltic LN/CWC ‘outliers’).

steppe-chalcolithic-migrations
Steppe-related migrations ca. 3100-2600 BC with tentative linguistic identification.

We didn’t know much about Sredni Stog or Corded Ware, and we still don’t. I can’t see the future, and I don’t have access to information from Reich-Jena or Copenhagen groups, and never have. But I just don’t see the need to explain Corded Ware as derived from (coeval) Early Yamna, and I haven’t since the 2015 papers. It was not the best explanation for the data that was published, and the more information we receive, the less sense this theory makes.

However, I guess we will see some groups still resorting to the good old Yamnaya ancestral component™ = Indo-European no matter what, consciously ignoring that a proportion of ancestral components (some combination of EHG:CHG:WHG in this case) means nothing without a proper explanation of their precise temporal and regional origin, and how they connect with Yamna; just like the CHG ancestry = Indo-European trend we are living right now does not make any sense.

Publishing only selected results after trying every possible combination of samples with bioinformatic tools does not help strengthen this connection, either.

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