The term Ancient East Eurasian, alternatively also known as East Eurasian or Eastern Eurasian, is used in population genomics to describe the genetic ancestry and phylogenetic relationship of diverse populations primarily living in the Asia-Pacific region, belonging to the "Eastern Eurasian clade" of human genetic diversity, [1] [2] [3] [4] [5] [6] and which can be associated with the Initial Upper Paleolithic (IUP) wave, following the Out of Africa migration at least 60,000 years ago. [4] [6]
Ancient East Eurasians, modern humans of the Initial Upper Paleolithic (IUP) wave, are suggested to have diverged from Ancient West Eurasians around 48,000 years ago from a population hub likely on the Persian plateau, and expanded across Eurasia through a star-like expansion pattern at least 45,000 years ago. [7] [6]
Ancient East Eurasians started to diversify among themselves as early as 45,000 years ago. [6] This diversification may possibly be related to the development of two major IUP-affiliated types of material culture: "microlithic blade" (or microblade) and "core & flake" (or CAF assemblages). Specific IUP populations represented by specimens found in Europe, Central Asia, and Siberia, such as the Ust'-Ishim man, Bacho Kiro, Oase 2, and Kara-Bom, that are associated with the spread of microblade sites, are inferred to have used inland routes northward into Eurasia. [8] [9] [10] In contrast, IUP populations represented by specimens found in South, Southeast, and East Asia, as well as Oceania, such as the Tianyuan man, that are associated with the spread of core & flake sites, are inferred to have used a Southern dispersal route along the southern coast of Asia. [11] [12] [13]
The IUP populations that expanded through Southern dispersal route are inferred to be the ancestors of all modern East Eurasian populations (dubbed as "East Eurasian Core"; EEC). EEC populations subsequently diversified rapidly from South and Southeast Asia at least 40,000 years ago, and became ancestral to modern populations in Eastern Eurasia, Oceania, and the Americas, notably East Asians, Southeast Asians, Indigenous Siberians, Aboriginal Australians, Papuans, Pacific Islanders, Indigenous Americans, and partly South and Central Asians. [7] [14] [15] [16] [17] [18] [19] [20] [21] South Asia may have acted as central hub for the peopling of Eastern Asia and Australasia. [22]
Major East Eurasian ancestry lineages which contributed to modern human populations include the following: [14]
The "Australasian," "Ancient Ancestral South Indian," and "East and Southeast Asian" lineages display a closer genetic relationship to each other than to any non-Asian lineages, as well as being closer to each other than to any of the early East Eurasian IUP lineages (Bacho Kiro etc.), and together represent the main branches of "Asian-related ancestry", which diverged from each other at least 40,000 years ago. [14] The Australasian lineage however received higher archaic admixture in the Oceania region, and may also harbor some small amounts of "xOoA" admixture from an earlier human dispersal, which did not contribute to any other human population. Alternatively, Australasians can be described as nearly equally admixture between a "Basal East Asian" source (represented by Tianyuan or Onge) and a deeper East Eurasian lineage not sampled yet. [7] [1] [14] : 11
Traces of an unsampled deeply diverged East Eurasian lineage can be observed in the genome of ancient and modern inhabitants of the Tibetan Plateau. While modern Tibetans mostly derive their ancestry from a northern East Asian source (specifically Yellow River farmers), a minor, but significant contribution stems from a deeply diverged East Eurasian local "Ghost population" that was distinct from other deeply diverged lineages such as Ust'Ishim, Hoabinhian/Onge or Tianyuan, representing the local Paleolithic population of the Tibetan Plateau. [26] [27] The remains of a 7,100 year old specimen from Yunnan, known as Xingyi_EN, were found to represent a new deeply branching Basal Asian lineage, which is closely related to the inferred Ghost ancestry among Tibetans. [28]
Deeper IUP-associated East Eurasian lineages have been associated with the remains of the Oase and Bacho Kiro cave specimens in southeastern Europe, and represent an inland migration northwards associated with the dispersal of IUP material culture, deeply diverged from all other East Eurasian populations (EEC). These deep East Eurasian populations did not contribute significantly to later Eurasian populations, except variable amounts of geneflow to subsequent Upper Paleolithic European groups, such as the Goyet Caves specimen (GoyetQ116-1; c. 17–23%) associated with the Aurignacian culture, or the Sungir specimen (c. 0–14%) associated with the Gravettian culture (via Aurignacian geneflow). In contrast, the Upper Paleolithic European Kostenki-14 specimen, did not display evidence for IUP-affilated admixture. [7] [29] [21] [14] [30] [31]
A deep IUP-affilated lineage may have also contributed ancestry (up to 39%) to the Tianyuan man, explaining the observed affinity between Tianyuan and GoyetQ116-1, as well as GoyetQ116-1 and BachoKiro_IUP. This variegated East Eurasian substrate found among the GoyetQ116-1 specimen may hint to "yet undescribed complexities within the IUP population branch". [31] [7] This lineage may also be affilated with IUP sites in Siberia and Northwest China, but currently no archaeogenetic data for these sites is available. [21]
The exact relationship of the Ust'-Ishim man from Siberia to other IUP/East Eurasian lineages is not well resolved yet. The Ust'-Ishim man forms a near trifurication between West Eurasian (Kostenki-14) and IUP/East Eurasian lineages, but shares a short period of evolutionary drift with Eastern Eurasians. [7] [6] The Ust'Ishim lineage is inferred to have not contributed ancestry to modern human populations. [21]
... and the split between EEC and WEC, with the former leaving the Hub18, 46 kya (allowing the time for them to reach Ust'Ishim and Bacho Kiro by ~45 kya).
{{cite journal}}
: CS1 maint: numeric names: authors list (link)... ancient and modern genomic studies appear to favor a southern route into East Asia for the majority of genetic diversity present there today. ... If these East Asian IUP sites were to be linked to populations related to Ust' Ishim it would appear these people left no detectable genetic legacy in modern East Asia. It may also be found that the material at some of these IUP sites was created by populations derived from East Asian lineages linked to or branching from Tianyuan.
The results indicated that all modern East Asians, Northeast Asians, and Native Americans, including this Jomon individual, are descendants of populations that reached the eastern side of the Eurasian continent via the southern route.
the southern migration wave seems to have diversified into the local populations in East Asia (defined in this paper as a region including China, Japan, Korea, Mongolia, Taiwan and Southeast Asia), and the northern wave, which probably runs through the Siberian and Eurasian steppe regions and mixed with the southern wave, probably in Siberia.
Via the southern route, ancestors of current Asian populations reached Southeast Asia and a part of Oceania around 70000–50000 years ago, probably through a coastal dispersal route (Bae et al., 2017). The oldest samples providing the genetic evidence of the northern migration route come from a high-coverage genome sequence of individuals excavated from the Yana RHS site in northeastern Siberia (Figure 2), which is about 31600 years old (Sikora et al., 2019).
Population genomic studies on present-day humans7,8 have exclusively supported the southern route origin of East Asian populations.
A single major migration of modern humans into the continents of Asia and Sahul was strongly supported by earlier studies using mitochondrial DNA, the non-recombining portion of Y chromosomes, and autosomal SNP data [42–45]. Ancestral Ancient South Indians with no West Eurasian relatedness, East Asians, Onge (Andamanese hunter–gatherers) and Papuans all derive in a short evolutionary time from the eastward dispersal of an out-of-Africa population [46,47]. The HUGO (Human Genome Organization) Pan-Asian SNP consortium [44] investigated haplotype diversity within present-day Asian populations and found a strong correlation with latitude, with diversity decreasing from south to north. The correlation continues to hold when only mainland Southeast Asian and East Asian populations are considered, and is perhaps attributable to a serial founder effect [50]. These observations are consistent with the view that soon after the single eastward migration of modern humans, East Asians diverged in southern East Asia and dispersed northward across the continent.
Inferences from nuclear (51), Y chromosome (52), and mitochondrial genome (53) data support an early migration of modern humans out of Africa and into Southeast Asia using a southern route by at least 60 ka. Patterns of genetic variation in recent human populations (11, 54, 55) recognize Southeast Asia as an important source for the peopling of East Asia and Australasia via a rapid, early settlement.
Based on the above findings, some scholars have proposed that the specific diffusion path of early modern humans in the south was quite complex, possibly including both coastal routes (some sites may be submerged under the sea) and inland routes. Field J et al.'s minimum cost path analysis based on GIS technology confirmed this: early modern humans formed multiple paths during their diffusion, and their inland paths were mostly based on rivers as migration corridors, such as the Indus River and the Narmada River in the Indian Peninsula.
To understand the demographic pattern, current ancient DNA (aDNA) studies highlight India as a central hub for the later colonization of Asia and Australia
our results reject previously suggested sources of gene flow into the Tibetan lineage13,35,36, including deeply branching Eastern Eurasian lineages, such as the 45,000-year-old Ust'-Ishim individual from southern Siberia, the 40,000-year-old Tianyuan individual from northern China, and Hoabinhian/Onge-related lineages in southeast Asia (Supplementary Fig. 10), suggesting instead that it represents yet another unsampled lineage within early Eurasian genetic diversity. This deep Eurasian lineage is likely to represent the Paleolithic genetic substratum of the Plateau populations.
{{cite journal}}
: CS1 maint: multiple names: authors list (link)