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DFT calculations shows an unexpected mechanism in the photoredox/copper-catalyzed carbocyanation of 1,3-diene, which involves CuI-only catalysis and the single electron transfer from the allyl radical to the oxidized photocatalyst.

DFT calculations show that the difference in reactivity caused by different raw materials (aryl halides/trifluoromethanesulfonate) is due to the different formation rates of intermediates in copper and palladium catalytic cycles.

The analysis of ancient DNA and paleoproteomics can identify biological materials, such as fossils, construct phylogenetic relationships between extinct and extant species, and has been widely applied in archaeology and paleontology. In general, proteins degrade more slowly than DNA and could be persevered in fossils over 60 million. Although less phylogenetic information was obtained than ancient DNA, paleoproteomics analysis becomes an indispensable method for studying biological evolution and hominins behaviours with its high throughput, low cost, and low contamination. Based on several cases of applying paleoproteomics analysis in archaeological and paleontological sites from East Asia, I will present two main methods, LC-MS/MS and MALDI-TOF MS, and how paleoproteomics reveals the evolutionary history and behaviours of hominins in East Asia, aiming to provide a research background of this field.

In a new mechanism for photosensitizer-free visible-light-mediated gold-catalyzed cross-coupling, the π–π complex between aryldiazonium salts and arylboronic acids acts as a photoinitiator.

Density functional theory calculations were performed on a prototype of three-component reactions involving aryl iodides, 2,6-substituted aryl bromides, and acrylates to understand the construction of axially chiral biaryls through the palladium/chiral norbornene cooperative catalysis (Nat. Catal. 2020, 3, 727733). The reaction is established to occur in sequence through oxidative addition of aryl iodide to Pd(0), norbornene insertion, CH activation, oxidative addition of aryl bromide to Pd(II), CC reductive elimination, norbornene extrusion, alkene insertion, and -H elimination. The CH activation is characterized as the rate-determining step, and the oxidative addition of aryl bromide on Pd(II) control the enantioselectivity of the reaction. The construction of more favorable (S)-CC axial chirality is attributed to the smaller steric repulsion between the ortho-methyl group of aryl bromide and the norbornene moiety. The theoretical results rationalize the reaction sequence of aryl iodide and aryl bromide on both Pd(0) and Pd(II) and clarify the substantial role of the ortho-ester group in the aryl bromide.

At Quesang on the Tibetan Plateau we report a series of hand and foot impressions that appear to have been intentionally placed on the surface of a unit of soft travertine. The travertine was deposited by water from a hot spring which is now inactive and as the travertine lithified it preserved the traces. On the basis of the sizes of the hand and foot traces, we suggest that two track-makers were involved and were likely children. We interpret this event as a deliberate artistic act that created a work of parietal art. The travertine unit on which the traces were imprinted dates to between ∼169 and 226 ka BP. This would make the site the earliest currently known example of parietal art in the world and would also provide the earliest evidence discovered to date for hominins on the High Tibetan Plateau (above 4000 m a.s.l.). This remarkable discovery adds to the body of research that identifies children as some of the earliest artists within the genus Homo.

Metal chalcogenides as anode materials of sodium ion batteries show excellent performances. However, there is still much confusion about sodium storage mechanisms. Here, CoSe2 is used as a model of metal selenides to disclose these electrochemical reactions in ether-based electrolytes, where Cu species from Cu foil gradually permeate into the electrode and replace Co to bind with Se upon cycling. The driving force of this transition in thermodynamics can be qualitatively illustrated by Hard-Soft-Acid-Base theory, as confirmed by a series of metal selenides. Because Cu species need to pass through solid-electrolyte-interphase (SEI) during this transition, electrolytes and voltages, which control the formation of SEI, become important in kinetics. To our knowledge, it is the first time to realize the crucial role of SEI in this transition. These results are important to understand the electrochemical properties of metal selenides in sodium ion batteries.

The work by MacMillan et al. ( Angew. Chem., Int. Ed. 2018, 57, 12543-12548) developed an IrIII/NiII-metallaphotoredox-catalyzed difluoromethylation strategy of aryl bromides using CHF2Br as the CHF2 reagent in the presence of tris(trimethylsilyl)silane. Here, we present a density functional theory (DFT)-based computational study to understand special dual catalysis promoting the C(sp2)-C(sp3) coupling. The calculated results show that the energetically more favorable pathway involves the reductive quenching of a photocatalyst (IrIII/*IrIII/IrII/IrIII) and a Ni0-initiated catalytic cycle (Ni0/NiI/NiIII/NiI/Ni0 or Ni0/NiII/NiIII/NiI/Ni0). The calculations reveal not only the mechanistic details delivering the difluoromethylarene product but also the molecular-level picture of the generation of Ni0 species from the NiII precatalyst. Moreover, the calculations also rationalize the observed stoichiometric effect of CHF2Br in the reactions of aryl bromides with different substituted groups.

This density functional theory (DFT) study reveals a detailed plausible mechanism for the Sc-catalyzed C-H cycloaddition of imidazoles to 1,1-disubstituted alkenes to form all-carbon quaternary stereocenters. The Sc complex binds the imidazole substrate to enable deprotonative C2-H bond activation by the Sc-bound α-carbon to afford the active species. This complex undergoes intramolecular cyclization (C═C into Sc-imidazolyl insertion) with exo-selectivity, generating a β-all-carbon-substituted quaternary center in the polycyclic imidazole derivative. The Sc-bound α-carbon deprotonates the imidazole C2-H bond to deliver the product and regenerate the active catalyst, which is the rate-determining step. Calculations illuminate the electronic effect of the ancillary Cp ligand on the catalyst activity and reveal the steric bias caused by using a chiral catalyst that induce the enantioselectivity. The insights can have implications for advancing rare-earth metal-catalyzed C-H functionalization of imidazoles.

We report the first computational study on a nickel hydride HAT-initiated catalytic reaction, a novel hydrodefluorination of CF3-substituted aryl alkenes to afford gem-difluoroalkenes. This study provides detailed mechanistic insights into the reaction, including HAT from NiH to CC, a carbon radical rebound to nickel to facilitate chemoselective defluorination, and a two-state reactivity of Ni(II) enabling σ-bond metathesis with PhSiH3 to regenerate the catalyst. The findings can have implications for developing new metal hydride HAT-initiated reactions.

Density functional theory calculations have been carried out to elucidate the mechanism, enantio-, regio-, and chemoselectivities, and the role of the NHC ligand in the Ni/NHC-catalyzed alkylation of fluoroarenes with alkenes, a new strategy that exclusively achieved enantio- and regioselective C–H activation over multiple C–F bonds (Angew. Chem., Int. Ed., 2019, 58, 13433–13437). The reaction is found to follow a concerted ligand–ligand hydrogen transfer (LLHT) mechanism instead of the stepwise oxidative addition/alkene insertion mechanism. The high R-enantioselectivity originates from the stronger agostic interaction in the R-configuration than that in the S-type enantiomer, the exclusive endo-regioselectivity is controlled by the stronger electrostatic force of the Ni(0) catalyst with the terminal carbon atom than that with the internal carbon atom in the alkene, and the excellent chemoselectivity of C–H activation over C–F activation is attributed to the more favorable concerted ligand–ligand hydrogen transfer (LLHT) mechanism of C–H activation than the stepwise mechanism of the C–F activation. The enhanced reactivity with the NHC ligand is attributed to the increase in the HOMO level of the catalyst via the highly electron-donating effect of the NHC ligand.

Density functional theory calculations were performed to understand the distinctly different reactivities of o-carboxylate-substituted aryl halides and pristine aryl halides toward the PdII-catalyzed γ-C(sp3)-H arylation of secondary alkylamines. It is found that, when 2-iodobenzoic acid (a representative of o-carboxylate-substituted aryl halides) is used as an aryl transfer agent, the arylation reaction is energetically favorable, while when the pristine aryl halide iodobenzene is used as the aryl transfer reagent, the reaction is kinetically difficult. Our calculations showed an operative PdII/PdIV/PdII redox cycle, which differs in the mechanistic details from the cycle proposed by the experimental authors. The improved mechanism emphasizes that (i) the intrinsic role of the o-carboxylate group is facilitating the C(sp3)-C(sp2) bond reductive elimination from PdIV rather than facilitating the oxidative addition of the aryl iodide on PdII, (ii) the decarboxylation occurs at the PdII species instead of the PdIV species, and (iii) the 1,2-arylpalladium migration proceeds via a stepwise mechanism where the reductive elimination occurs before decarboxylation, not via a concerted mechanism that merges the three processes decarboxylation, 1,2-arylpalladium migration, and C(sp3)-C(sp2) reductive elimination into one. The experimentally observed exclusive site selectivity of the reaction was also rationalized well.

The hydroformylation reaction is used on a large industrial scale to convert olefins and synthesis gas (CO + H2) into aldehydes. Researchers have recently discovered that a class of cationic Co(II)...

A manganese-catalyzed site- and enantiodifferentiating oxidation of C(sp3)-H bonds in saturated cyclic ethers has been described. The mild and practical method is applicable to a range of tetrahydrofurans, tetrahydropyrans, and medium-sized cyclic ethers with multiple stereocenters and diverse substituent patterns in high efficiency with extremely efficient site- and enantiodiscrimination. Late-stage application in complex biological active molecules was further demonstrated. Mechanistic studies by combined experiments and computations elucidated the reaction mechanism and origins of stereoselectivity. The ability to employ ether substrates as the limiting reagent, together with a broad substrate scope, and a high level of chiral recognition, represent a valuable demonstration of the utility of asymmetric C(sp3)-H oxidation in complex molecule synthesis.

The Ganjia Basin in Xiahe County, Gansu Province, China, is located on the northeastern edge of the Tibetan Plateau. The area lies in the transitional zone between the Plateau ethnic groups dominated by ancestral Tibetans, and the Central Plains dynasties dominated by ancestral Han in history. The Ganjia Basin is therefore well suited to studying the history of the intermixing of the Han and Tibetan peoples. In this study, we collected samples of organic materials from two ancient cities, Bajiaocheng (BJC) and Sirougucheng (SRGC), in the Ganjia Basin, which were used for radiocarbon dating. Our aims were to determine the construction times and function of the cities, based on the radiocarbon ages, Bayesian age modeling, and the analysis of relevant historical records. The results are used to discuss the role of the Ganjia Basin in the conflicts between and the integration of the two ethnic groups during the historical period. We conclude that BJC was established during 663–732 CE (Common Era); its early occupation history can be divided into an initial establishment phase (670–780 CE) and a phase of regeneration (880–1030 CE). SRGC was probably built at the time of the transition between the Song and Yuan dynasties (∼1271 CE). Combining the dating results with an analysis of the architectural styles and historical records, we conclude that BJC was originally built by the Tubo Kingdom as a military stronghold, and its major functions were military, economic and religious, and to support the major eastward expansion of the Tubo. SRGC was most likely a temple-focused city intended to promote Tibetan Buddhism which was a major political and religious leadership for the Tibetans at that time, reflecting changes in the status of different religions in the Ganjia Basin. In addition, the intermixing and blending of the Han and Tibetan groups, reflected by the human activities in the Ganjia Basin, was an important demographic and cultural foundation for the formation of the culturally-diverse but spiritually-united modern Chinese people.

This work presents a density functional theory (DFT) study on the mechanism and origins of enantio- and regioselectivities in dual photoredox/chiral Bronsted acid-catalyzed asymmetric Minisci-type addition of carbon-centered radicals to N-heteroarenes [Science, 2018, 360, 419-422]. The previously proposed mechanism has been partially revised. First, photoexcited *[IrIII] is reductively quenched by TRIP anion rather than the experimentally proposed neutral radical generated from the chiral Bronsted acid cycle. Second, final product formation involves a hydrogen-atom transfer (HAT) from a neutral radical intermediate to the TRIP radical, instead of single-electron transfer (SET) to *[IrIII]. The TRIP catalyst has been shown to play a triple role by reductively quenching *[IrIII] with its anion form, activating the substrate, and inducing asymmetry. The calculated results rationalize the experimentally observed enantio- and regioselectivities and reveal that the enantioselectivity of the reaction originates from the hydrogen-bond interaction between TRIP and the N-H group of the carbon-centered radical, and the regioselectivity arises from the electron-withdrawing inductive effect from the protonated N-atom and the intramolecular hydrogen-bond interaction between the acetylamino group and the protonated pyridine ring. We also provide explanations for the experimentally observed a dramatic decrease in enantioselectivity when changing substrate or radical precursor and rationalize the solvent-controlled switch of regioselectivity.

In 2010, geneticists reported the mitochondrial DNA and nuclear DNA sequences of a fragment of hominin phalanx found in Denisova cave, in the Altai Mountains in Russia, and the discovery of a new archaic human group which they named “Denisovans”. Subsequently, significant progress has been made in research on Denisovans. This paper reviews and summarizes recent achievements and advances in Denisovan studies, especially in chronology, archaeology, anthropology and genetics, over the past decade, with the aim of encouraging in-depth research in related fields in China. Comprehensive geochronological studies in Denisova cave suggest that Denisovans and Neanderthals may have occupied the cave during the interval of 287−55 ka (thousand years ago) and during 193−97 ka. Direct dating of hominin fossils, or of strata containing hominin fossils, indicates that Denisovans occupied the cave during 195−52 ka, while there is evidence of Neanderthals occupying the cave during 14.7−9.1 ka. These results reflect the long occupation history of Denisovans and Neanderthals in Denisova cave. In addition, the dating of the Xiahe mandible, from Baishiya karst cave (Xiahe County, Gansu Province, China) in the northeastern Tibetan Plateau, indicates that this is the first Denisovan fossil discovered outside Denisova cave, and suggests that Denisovans occupied the Tibetan Plateau at least at 160 ka, in the late Middle Pleistocene. This extends the spatial distribution of Denisovans from the Altai Mountains to the Tibetan Plateau and indicates that the Xiahe Denisovans may have been adapted to the extremely cold and hypoxic environment of the plateau. Lithic assemblages from Denisova cave include both Levallois and blade technologies produced by either Denisovans or Neanderthals, or both, who coexisted in the cave for a long time. However, preliminary analysis of lithic artifacts collected from Baishiya Karst cave indicates the dominance of simple core and flake technology. In consideration of long coexistence of two archaic humans in Denisova cave, and the archeological work in Baishiya Karst cave is still in its infancy stage, the cultural connotation of Denisovans needs further comprehensive study. Considering the long coexistence of the two archaic humans in Denisova cave, and that archeological work in Baishiya karst cave is still at a preliminary stage, the cultural connotations of the Denisovans require further comprehensive study. The fragments of Denisovan fossils found in Denisova cave provide limited evidence of the morphological characteristics of the phalanx and teeth, while the Xiahe mandible provides more extensive and important evidence of the morphological characteristics of the mandibles of Denisovans. The present study shows that the overall morphological characteristics of the phalanx are closer to those of modern humans than to Neanderthals, although the size of the molars is much greater than that those of Neanderthals and modern humans; in addition, the mandible has several features similar to those of archaic Homo sapiens in East Asia. However, due to the limited fossil evidence, the morphological differences between Denisovans and other archaic humans remain to be comprehensively documented. In addition, in contrast to the Neanderthals’ wide genetic contribution to modern humans, Denisovans only genetically contributed to modern populations in Oceania, East Asia, South Asia and America, and they exhibit a gene flow from superarchaic humans. In addition, multiple deeply differentiated branches may exist within the Denisovan population. These findings imply that Denisovans may have been more widely distributed in Asia than was previously thought and that they possess a more complex evolutionary history. At present, only one high-coverage Denisovan genome has been discovered in Denisova cave and no ancient DNA is preserved in the Xiahe mandible, which limits our understanding of other Denisovan branches. Although we still know little about Denisovans, we anticipate that future in-depth archaeological studies at Baishiya karst cave will provide additional important information on the physical morphology of Denisovans, their genetic characteristics and behavioral culture, and will elucidate the adaptation mechanism of Denisovans to high-altitude environments. In addition, we expect that an increasing number of new discoveries and multidisciplinary endeavors will shed additional light on the Denisovans and thus contribute to the study of human evolution in East Asia.

By performing density functional theory (DFT) calculation, this work aims at understanding the nonconventional meta-C-H arylation reaction of electronic-rich arenes with aryl iodide via a Pd/quinoxaline-based ligand/norbornene cooperative catalysis. The reaction is indicated to be initiated either from the ortho-C-H carbopalladation to give the meta-monoarylation product via a sequence of subsequent steps, including norbornene insertion, meta-C-H activation, oxidative addition, and reductive elimination via the Pd(II)/Pd(IV)/Pd(II) redox cycle, norbornene extrusion, and protodepalladation, or from the para-C-H carbopalladation to form the meta-diarylation product via two sequential arylation processes following similar mechanisms. The initial carbopalladation process promoted by the ligand is characterized as the rate-determining step of the reaction. The calculated mechanism shows the distinct role of the norbornene as a transient mediator that enables the final C-H arylation at the same meta-position wherever the initial carbopalladation occurs at either ortho- or para-position. The Pd/ligand/norbornene cooperative catalysis is essential for achieving the exclusive meta-selectivity of the C-H arylation of electron-rich arenes.

The C–N coupling of alkyl electrophiles for amine synthesis is a less-developed area in comparison with that of aryl electrophiles largely because of the difficulty in product-generating C(sp3)–N r...

Archaeological research has documented the migration of Neolithic farmers onto the Tibetan Plateau by 4000 BC. How these incoming groups interacted, if at all, with local indigenous foragers, however, remains unclear. New archaeobotanical and zooarchaeological data from the Zongri site in the north-eastern Tibetan Plateau suggest that local foragers continued to hunt but supplemented their diet with agricultural products in the form of millet. The authors propose that, rather than being grown locally, this millet was acquired via exchange with farmers. This article highlights how indigenous foragers engaged in complex patterns of material and cultural exchange through encounters with newly arrived farmers.

Recent environmental archeological evidence has started to throw light on both the timing and processes of human colonization of the Tibetan Plateau (TP). Yarlung Tsangpo (YT) valley, a very important region of the southern TP for occupation, is home to not only modern Tibetans but also their ancestors. However, a lack of suitable sedimentary strata has limited the establishment of a secure chronology. Here, we report on a new stratigraphic section with prehistoric pottery and cultural layers that was discovered on a terrace of the YT at Liena, in Nyingchi County. The cultural layers are overlain by, and bedded within, eolian and lacustrine sediments. We used the quartz Optically Stimulated Luminescence (OSL) method to date 11 samples and performed geochemical analysis on 100 samples to derive paleoenvironmental indicators. The OSL analysis gave an age of 4.3 ka BP for the cultural layer, which makes it the earliest human activity in the YT valley of Nyingchi to date. In addition, commencement of eolian deposition was dated to at least 8.3 ka, coinciding with the Holocene warm period. We discuss possible causal factors for human occupation in the valley and show that climatic changes played a crucial role in prehistoric human migration c. 8.3–4.3 ka BP. Before the early Holocene, most of the river terraces in the valley were being actively reworked by rivers or covered by lakes. So there were no suitable places for occupation by ancient populations. With the recession of dammed lakes during the Holocene warm period, the relatively flat and wide valley terraces, blanketed with rich eolian deposits (such as sandy loess), provided an attractive place for ancient people engaged in nomadic and even agricultural activities. Hence, the climate conditions of the Holocene warm period drove the environmental changes that provided favorable conditions for ancient human activities.

With two distinct active sites, 2-hydroxy-2′-amino-diphenylethyne derivatives can offer benzofuro­[3,2-c]­quinolinones via the O-attack/N-carbonylation cyclization or indolo­[3,2-c]­coumarins via the N-attack/O-carbonylation cyclization. This work presents a density functional theory-based computational study to understand the mechanism and origin of the palladium­(II)-catalyzed regiodivergent reactivity of diphenylethyne derivatives. It is indicated that the reaction features a palladium­(II)–counterion–ligand cooperative catalysis. The O-attack/N-carbonylation cyclization mainly benefits from the inductive effect of the rigid electron-withdrawing bidentate nitrogen ligand and the stabilization of the 3c-4e bond between the trifluoroacetate (TFA) anion and the hydroxyl group in the substrate for the precursor and transition state, while the viability of the N-attack/O-carbonylation cyclization stems intrinsically from the stronger nucleophilicity of the N atom as well as the important π–π interaction between the flexible electron-rich bidentate phosphine ligand and the substrate. Moreover, these calculations propose an unconventional reductive elimination mechanism for the transformation from Pd­(II) to Pd(0), where the intramolecular nucleophilic attack of the N/O atom on the carbonyl C atom results in the formal reductive elimination product. The calculated overall barriers of 14.8 kcal/mol for Pd­(TFA)2 with the bidentate nitrogen ligand and 23.9 kcal/mol for Pd­(OTf)2 with the bidentate phosphine ligand are qualitatively consistent with the mild experimental conditions.

Alpine ecosystems on the Tibetan Plateau are being threatened by ongoing climate warming and intensified human activities. Ecological time-series obtained from sedimentary ancient DNA (sedaDNA) are essential for understanding past ecosystem and biodiversity dynamics on the Tibetan Plateau and their responses to climate change at a high taxonomic resolution. Hitherto only few but promising studies have been published on this topic. The potential and limitations of using sedaDNA on the Tibetan Plateau are not fully understood. Here, we (i) provide updated knowledge of and a brief introduction to the suitable archives, region-specific taphonomy, state-of-the-art methodologies, and research questions of sedaDNA on the Tibetan Plateau; (ii) review published and ongoing sedaDNA studies from the Tibetan Plateau; and (iii) give some recommendations for future sedaDNA study designs. Based on the current knowledge of taphonomy, we infer that deep glacial lakes with freshwater and high clay sediment input, such as those from the southern and southeastern Tibetan Plateau, may have a high potential for sedaDNA studies. Metabarcoding (for microorganisms and plants), metagenomics (for ecosystems), and hybridization capture (for prehistoric humans) are three primary sedaDNA approaches which have been successfully applied on the Tibetan Plateau, but their power is still limited by several technical issues, such as PCR bias and incompleteness of taxonomic reference databases. Setting up high-quality and open-access regional taxonomic reference databases for the Tibetan Plateau should be given priority in the future. To conclude, the archival, taphonomic, and methodological conditions of the Tibetan Plateau are favorable for performing sedaDNA studies. More research should be encouraged to address questions about long-term ecological dynamics at ecosystem scale and to bring the paleoecology of the Tibetan Plateau into a new era.

The origin, nature and timing of prehistoric human activity on the Tibetan Plateau has become a major research topic in recent years, and great progress has been made in the study of the earliest human activity on the plateau and in the origin of modern Tibetans. The earliest human presence on the plateau has been updated by two important new studies. Rich blade assemblages found in the excavation of the Nwya Devu site shows that modern humans occupied the interior region of the Tibetan Plateau, above 4600 m a.s. l., some 30−40 thousand years ago. Recently, a study of a human mandible fossil found in Xiahe County, Gansu Province, in the northeastern Tibetan Plateau, indicated that Denisovans occupied the Tibetan Plateau at least 160000 years ago, much earlier than the arrival of modern humans to the region. The latter study also implies that the high-altitude adaptation gene, which occurs widely among modern Tibetans and Sherpa, was probably contributed by local archaic humans, like the Xiahe Denisovans. These two studies not only point to the long and complex human history in the Tibetan Plateau, but they also indicate the complexity of human evolution in the Middle and Late Pleistocene in East Asia. Whether early Holocene hunter-gatherers had already permanently settled on the Tibetan Plateau before the arrival of millet and barley agriculture after the middle Holocene, has become another major research topic in the study of the prehistoric human history of the Tibetan Plateau. However, due to the current lack of reliable evidence for the seasonality of Paleolithic site occupations in the Tibetan Plateau, the issue remains difficult to resolve. The origin of modern Tibetans has been debated for decades. A new linguistic study of the phylogeny and the time depth of the original divergence of the Sino-Tibetan language, based on Bayesian phylogenetic analysis of 109 languages, indicates that Sino-Tibetan languages diverged during some 4200 to 7800 years ago, which points to Neolithic population dispersals to the Tibetan Plateau and their close relationship with modern Tibetans. In addition, a new genetic study, based on mitochondrial DNA (mtDNA) analyses of 8277 Tibetans and 58514 individuals from the surrounding populations, has traced the genetic legacy of modern Tibetans to the historical or even Neolithic periods. Calculation of the time depth of the two common haplogroups in modern Tibetans found in this study, implies that these two groups of populations originated in northern China between 6000 and 10000 years ago and differentiated between 4000 and 5200 years ago. Both of these studies are consistent with previous archaeological studies which propose that Neolithic and Bronze Age populations moved to the Tibetan Plateau from a substantial considerable of areas in North China. More importantly, the two studies further confirm the close relationships between Neolithic millet farmers and modern Tibetans, clarifying the origin of modern Tibetans. There have also been several new Paleolithic archaeological studies of the regions surrounding the Tibetan Plateau. A deeper understanding of the Initial Upper Paleolithic in North China, Mongolia and Siberia, and new findings of the Levallois technology in the Jinsitai and Tongtian cave sites in North China, indicate a dispersal route of Paleolithic populations from the north to the Tibetan Plateau. Other studies also propose possible population migration routes in the southeastern and southwestern plateau, although archaeological evidence is currently lacking. Together with the new Paleolithic archaeological findings for the Tibetan Plateau, it appears that different human groups, including Denisovans, Neanderthals and modern humans, were living in or around the Tibetan Plateau during the Middle to Late Pleistocene. Although recent studies provide new clues for understanding their inter-relationships, additional questions have arisen, and more multidisciplinary studies are needed in the future to address them. Above all, these new studies are crucial for understanding the mechanisms by which prehistoric humans spread to and in the Tibetan Plateau, and their adaptation to the high elevation environments. In addition, they shed new light on the origin of modern humans, as well as on human evolution in East Asia during the Middle and Late Pleistocene.