Transformations of steppe populations
Our paper presents a complete transect of the Samara region beginning with the Samara EHG hunter-gatherer (~5,600BCE)5 and ending with the Srubnaya culture (~1,850-1,200 BCE) and a singleton “Scythian” Iron Age individual (~300BCE). In eastern Europe outside the steppe, a new individual from the Karelia region resembles the two previously published EHG
individuals5 autosomally, but surprisingly belongs to Y-chromosome haplogroup J usually associated with Near Eastern populations (Supplementary Data Table 1). In a previous study5 it was shown that Yamnaya populations from the Samara region were a mixture of the EHG and a population of Near Eastern ancestry for whom present-day Armenians could be a surrogate. The Samara_Eneolithic from Khvalynsk II (~5,200- 4,000BCE) predates the Yamnaya by at least 1,000 years but had already begun admixing with this population, although the individuals of this population appear to be heterogeneous (Fig. 1) between EHG and Yamnaya. Taken as a whole, we estimate that they have ~74% EHG and ~26% Armenian related ancestry. The three Eneolithic individuals belong to Ychromosome haplogroups R1a, R1b, and Q1a; the last of these three is associated with present-day Siberian populations and Native Americans, while R1a and R1b were previously found in the two EHG hunter-gatherers5. These results suggest a great degree of continuity with the EHG for the Eneolithic population. The Yamnaya samples from Samara5 and Kalmykia1 and the Afanasievo1 population from the Altai form a tight cluster (Fig. 1, Extended Data Fig. 2). Our study includes new data from the later Middle Bronze Age population of the Poltavka culture (~2,900-2,200BCE), which
cluster with the Yamnaya and Afanasievo. The Poltavka also possess R1b Y-chromosomes (Supplementary Data Table 1), continuing the dominant Y-chromosome type found in the Yamnaya1,5. This group of populations have even less EHG ancestry than the Eneolithic population (Extended Data Table 3), estimated to be ~42-52% (Extended Data Fig. 3D). Admixture into steppe populations continued with the Potapovka culture (~2,500-1,900BCE)
and the Srubnaya culture (~1,850-1,200 BCE). Admixture in these later steppe populations is from a different source than in the earlier ones. For the Yamnaya/Afanasievo/Poltavka Steppe group, the statistics f4(EHG, Steppe; Armenian, LBK_EN) are negative, and the statistics f4(Steppe, Srubnaya; Armenian, LBK_EN) are positive, suggesting a different source of
population change during the EHG→Steppe transition and the later Steppe→Srubnaya transition. The Steppe group had ancestry related to Armenians and the Srubnaya had an additional source related to European farmers. This is also clear from the PCA where the Srubnaya differ from the Steppe group in the direction of European farmers, and in the ADMIXTURE analysis (Extended Data Fig. 2), which shows them to have an EEF/Anatolia
Neolithic-related component of ancestry not present in the Steppe group. Clearer evidence of this discontinuity is seen when we model different steppe populations as mixtures of Armenians and EHG (Extended Data Fig. 3A), and add Anatolia_Neolithic as a third ancestral population: this has no effect in fit for the earlier populations, but significantly improves fit for the Potapovka, Srubnaya, and eastern Sintashta and Andronovo populations. A discontinuity between earlier and later steppe populations is also suggested by the shift
from an R1b Y-chromosome gene pool into an R1a-dominated one in the Srubnaya (Supplementary Data Table 1). We caution that this does not mean that new populations migrated into the steppe as R1a was also detected in Eneolithic Samara and an outlier Poltavka individual (Supplementary Data Table 1); it is possible that R1a males continued to abide in the Samara region but were not included in the rich burials associated with the Yamnaya and Poltavka elites in the intervening period. It is unclear how the Srubnaya acquired farmer ancestry. One possibility is that contact between early farmer and steppe populations produced populations of mixed ancestry that migrated eastward to the Samara district and further east to form the Sintashta/Andronovo populations. A different possibility suggested in Ref. 1 is that the Corded Ware population of central/northern Europe migrated into the steppe. Our new data document the existence of farmer-admixed steppe populations in the European steppe and provide a plausible source for
the more eastward migrations of such populations. Further evidence for a connection between the Srubnaya and populations of central/south Asia—which is absent in ancient central Europeans including people of the Corded Ware culture and is nearly absent in present-day Europeans23—is provided by the occurrence in four Srubnaya and one Poltavka males of haplogroup R1a-Z93 which is common in present-day central/south Asians and Bronze Age people from the Altai24 (Supplementary Data Table 1). This represents a direct link between the European steppe and central/south Asia, an intriguing observation that may be related to the spread of Indo-European languages in that direction. Our results on European steppe populations highlight the complexity of their interactions with surrounding populations. At the earliest period, gene flow from a population related to Armenians, presumably from the south, diluted their EHG ancestry and created the mix of ancestry of the Yamnaya/Afanasievo/Poltavka group. Later, gene flow from a population
related to Anatolian and European farmers further diluted their EHG ancestry to create the Srubnaya/Sintashta/Andronovo group. This latter group resembled Late Neolithic/Bronze Age populations from mainland Europe (Fig. 1), and like them could be derived from both the farmers of Europe and Anatolia and the earlier steppe populations (Extended Data Fig. 3E).
The population history of mainland Europe and the steppe could be summarized as: (i) the dilution of hunter-gatherer ancestry by migrations from different parts of the Near East, (ii) the formation of populations of mixed hunter-gatherer/Near Eastern ancestry (Middle Neolithic/Chalcolithic in mainland Europe, and Eneolithic/Yamnaya/Poltavka on the steppe), and (iii) the migration of steppe populations into Europe during the Late Neolithic
(~2,500BCE) and of farmer populations into the steppe, leading to the formation of an array of populations of mixed ancestry encompassing both mainland Europe and the Eurasian steppe. Future research must elucidate how present-day populations emerged from the populations of the Bronze Age, and how populations from mainland Europe, the Eurasian
steppe, and Anatolia influenced and were influenced by those from the Near East and Central/South Asia.

 
Насколько я понял из англ. текста, смешение в степях местных охотников-собирателей с ближневосточными пришельцами(«армянами») происходило еще в энеолите, но усилилось с наступлением эпохи ранней бронзы, когда начала формироваться Циркумпонтийская Металлургическая Провинция. Вполне логично, что пришельцы, изначально обладавшие новой технологией бронзы, смогли занять более «элитарное» положение в степях, среди разрозненных и малочисленных местных обитателей, которые вели еще неолитический образ жизни. Новые знания и технологии смогли укрупнить старые местные сообщества и сформировать более многолюдные и технически оснащенные группы, после чего потомки местных охотников-собирателей вернули себе положение «элиты», растворив пришельцев, как старых, так и новых(с западноанатолийским «фермерским» следом). Уже из этих новых «племен» средней и поздней бронзы вышли покорители Индии. Как то так.
Как сейчас компьютеры и IT-технологии разносят по всему миру английские слова, так и тогда могла бронза разносить ИЕ изоглоссы,через connecting peoples. В добронзовые времена люди жили разрозненно, малочисленными коллективами, без особой нужды в контактах с близкими и дальними соседями. Все общение сводилось к примитивной торговле-обмену, а охота или земледелие позволяли быть самодостаточными. Потом появилась бронза, позволившая «объединять» через силу, появились вожди, боги, частная собственность, а самое главное-возможность заставить другого выполнять свои обязанности, взамен отбирая в свою пользу права покоренного. Родовой коллектив из неск. десятков-сотен человек уступил место племенам и союзам племен из тысяч-десятков тысяч человек. Тогда и возникла потребность в универсальном языке, который понимали бы не только в радиусе наблюдаемой округи, но и в нескольких сотнях километров. У папуасов этот процесс не произошел, поэтому у них до сих пор языковой бульон, а языком общения в государственном масштабе является ток-писин на основе англ. Нечто подобное было и в Евразии неолита. 

Авторы зафиксировали, что смешение между популяциями ближневосточного происхождения и восточно-европейских охотников-собирателей (EHG) началось еще в энеолите (5200-4000 до н.э.). Ямная культура из Самары и Калмыкии (5,3-4,7 тыс. лет назад), афанасьевская культура с Алтая (5,3-5,0 тыс. лет назад) и полтавкинская культура средней бронзы (4,9-4,7 тыс. лет назад ) довольно близки генетически, на графике РСА они образуют кластер «степной бронзы» (см. рисунок). Во всех этих культурах доминирует Y-хромосомная гаплогруппа R1b. 48-58% их предкового генофонда составляет ближневосточный компонент, который отличается от генофонда ранних земледельцев Европы и Анатолии, зато похож на генофонд современных армян. А вот «анатолийско-европейского земледельческого» компонента в генофонде степных культур этого времени не обнаруживается.
— имелся вклад ближневосточных предков в ямную культуру бронзового века;

 
Эти слова имеют научный вес? На них можно ссылаться, как на полновесный научный источник?