Violence in the first millennium BCE Eurasian steppe: Cranial trauma in three Turpan Basin populations from Xinjiang, China.

OBJECTIVES: Violence affected daily life in prehistoric societies, especially at conflict zones where different peoples fought over resources and for other reasons. In this study, cranial trauma was analyzed to discuss the pattern of violence experienced by three Bronze to early Iron Age populations (1,000-100 BCE) that belonged to the Subeixi culture. These populations lived in the Turpan Basin, a conflict zone in the middle of the Eurasian Steppe. METHODS: The injuries on 129 complete crania unearthed from the Subeixi cemeteries were examined for crude prevalence rate (CPR), trauma type, time of occurrence, possible weapon, and direction of the blow. Thirty-three injuries identified from poorly preserved crania were also included in the analyses except for the CPR. Data was also compared between the samples and with four other populations that had violence-related backgrounds. RESULTS: Overall, 16.3% (21/129) of the individuals showed violence-induced traumatic lesions. Results also indicated that most of the injuries were perimortem (81.6%), and that women and children were more involved in conflict than the other comparative populations. Wounds from weapons accounted for 42.1% of the identified cranial injuries. Distribution analysis suggested no dominant handedness of the attackers, and that blows came from all directions including the top (17.1%). Wounds caused by arrowheads and a special type of battle-ax popular in middle and eastern Eurasian Steppe were also recognized. DISCUSSION: A comprehensive analysis of the skeletal evidence, historical records, and archeological background would suggest that the raiding to be the most possible conflict pattern reflected by the samples. The attackers were likely to have been nomadic invaders from the steppe (such as the Xiongnu from historical records), who attacked the residents in the basin more likely for their resources rather than territory or labor force.

Masticatory properties in pre-modern Holocene populations from Northern China.

Recent studies indicate that evolution of the craniofacial skeleton is influenced by dietary behavior, which in turn alters masticatory efficacy and temporomandibular joint (TMJ) stability. In this study the mechanical properties of the masticatory system and the integrity of the TMJ in human populations from Northern China, dated to between 3800 BCE and 100 CE, were assessed. The results demonstrate that the mechanical efficiency is comparable to other modern human populations, though variations are present across different populations. While the ratio of overall weighted muscle efficiency for incisor loading vs. molar loading in pastoral and some recent agricultural groups is similar to early Homo sapiens, the ratio in more ancient agricultural groups is similar to the ratio in populations with heavy anterior paramasticatory activities, such as Neandertals, Inuits, and Native Americans. The TMJ vulnerability negatively correlates with the maxillary dental arch size, and positively with the condylar size. These findings suggest that there are multi-directional strategies in adaptation to heavy anterior teeth loading, such as increasing anterior teeth loading efficiency, increasing facial height, increasing facial breath and facial orthognathy, or decreasing anterior facial length. Furthermore, populations or individuals with a smaller dental arch and high biting efficiency could more easily injure the TMJ during unilateral loadings, which may explain the higher prevalence of TMJ disorders in modern humans, especially in women. These findings further reflect the impact of diachronic changes of the masticatory apparatus and lifestyle and their impact on oral health during recent human history.

Divided zygoma in Holocene human populations from Northern China.

OBJECTIVES: Divided zygoma (DZ) occurs in contemporaneous human populations, with the highest incidences in people from East Asia and Southern Africa. The present study examines the prevalence and variation of this condition in the Holocene populations of Northern China for the first time. METHODS: In this study, 1145 skulls from various human populations living in Northern China from the Neolithic Age to recent dynasties (5000-300 years BP) were examined. Specifically, cranial measurements and a CT scan were conducted to quantify craniofacial morphology. RESULTS: Fifteen skulls were identified with DZ, revealing an overall prevalence of 1.3% in the collection, while it was determined to be higher in North Asian and Northeast Asian regional groups. In skulls with unilateral DZ, the superior division of the zygoma was generally slender, while the inferior division of the zygoma was more robust. In skulls with bilateral DZ, the maxillae were generally more laterally extended. Moreover, unilateral DZ skulls displayed differences in cortical bone thickness between two sides of the facial skeleton. DISCUSSION: In context, the distribution pattern within these data points toward a greater prevalence of the DZ phenotype in North and Northeast Asian regional groups, suggesting a hypothesis that the DZ trait is more frequent in populations characterized by flat and broad faces. Accordingly, further studies into the DZ condition will deepen our understanding of developments in plasticity, variation, and recent evolution of the human cranium.

Intentional cranial modification from the Houtaomuga Site in Jilin, China: Earliest evidence and longest in situ practice during the Neolithic Age.

OBJECTIVES: Intentional cranial modification (ICM) was a long-established tradition used to reshape the head. Unfortunately, motivation of the act is unclear. It has been found in recent and contemporary human populations throughout the Old and New Worlds, yet the drawback of the quest into the origin, diffusion, and meanings of ICM is the lack of early materials for scientific examination. This study reports the discovery of ICM from the Neolithic Houtaomuga Site in Northeast China and the importance in deepening our knowledge of this intriguing tradition. MATERIALS AND METHODS: Twenty-five skeletons unearthed from the Neolithic cultural Phases 1-4 in the Houtaomuga Site were visually screened for ICM features. Cranial measurements were conducted to quantify the degree of variation in the modified skulls and typical ones were computer tomography (CT) scanned to obtain a diploë structure and 3D model. RESULTS: Eleven skulls carrying signs of ICM from both sexes varying in age from juveniles to full adults were identified ranging from 12,000 BP to 5,000 BP. Three types of modification patterns were observed and most of them were of typical fronto-occipital modification pattern. In particular, there were remarkable variations in the curvature of the crania along the sagittal direction. DISCUSSION: Overall, the antiquity as well as the cultural and genetic continuity of the population in Houtaomuga Site demonstrated the earliest confirmed ICM cases from the easternmost Old World, and the longest in situ duration of ICM practice at one single Neolithic site. This circumstance largely contributes to our understanding of the origins and distribution of ICM in Eurasia and the American continent.

Diachronic changes in craniofacial morphology among the middle-late Holocene populations from Hehuang region, Northwest China.

OBJECTIVES: This study analyzes craniofacial shape variation in the Hehuang region of Northwest China within a population genetic framework, and takes a diachronic approach to explore the relationship betwee cultural discontinuity and biological continuity/discontinuity in the Hehuang region during the middle to late Holocene. MATERIALS AND METHODS: The sample comprises 76 adult skulls from five archaeological sites, ranging from 4,500 to 1,530 BP. 3D geometric morphometrics, multivariate statistics, quantitative evolutionary genetic and biodistance analyses were performed to study the diachronic variation in craniofacial morphology. Analyses were performed on two cranial modules: the face and the cranial vault, across three major diachronic groups representing the late Neolithic (LNA), the Bronze Age (BA), and the Han-Jin dynasty (HD). RESULTS: Average regional FST for both cranial modules was low, indicating relatively greater variation within diachronic groups than among them. While the LNA and BA groups did not show any significant differences in facial and vault shape, significant craniofacial shape changes were detected between the BA and HD groups. DISCUSSION: The consistent craniofacial morphology during the LNA and the BA, and the shift in morphology between the BA and the HD indicates that cultural discontinuity does not always coincide with biological discontinuity. The Hehuang population evolved in situ with few changes, despite cultural and dietary changes, until the HD when migrations from the Central Plains are associated with extra-local gene flow to the area.

Possible case of pressure resorption associated with osteoarthritis in human skeletal remains from ancient China.

Osteoarthritis, one of the most common pathological conditions observed in human skeletal remains, is traditionally thought to only affect the structures within the joint capsule. We examined the osteoarthritic distal femora of an individual from Ancient North China, ca. 475-221 BCE. The standard signs of osteoarthritis, marginal lipping and extensive eburnation, were observed in the patellofemoral compartment of the knee joint. In addition however were bilateral pressure-caused fossae on the extra-articular anterior surfaces of the distal femora 10 mm proximal to the large osteophytes at the apex of the patellar surfaces. Anatomy and possible pathogenesis of knee arthritis are explored in order to come to a tentative aetiology of the extra-articular lesions. These lesions are suggested to be a new criterion for identifying severe knee arthritis. The osteological phenomenon is then placed into archaeological context of the Warring States period of ancient China.

Locomotion-Related Population Cortical Ca2+ Transients in Freely Behaving Mice.

Locomotion involves complex neural activity throughout different cortical and subcortical networks. The primary motor cortex (M1) receives a variety of projections from different brain regions and is responsible for executing movements. The primary visual cortex (V1) receives external visual stimuli and plays an important role in guiding locomotion. Understanding how exactly the M1 and the V1 are involved in locomotion requires recording the neural activities in these areas in freely moving animals. Here, we used an optical fiber-based method for the real-time monitoring of neuronal population activities in freely moving mice. We combined the bulk loading of a synthetic Ca2+ indicator and the optical fiber-based Ca2+ recordings of neuronal activities. An optical fiber 200 µm in diameter can detect the coherent activity of a subpopulation of neurons. In layer 5 of the M1 and V1, we showed that population Ca2+ transients reliably occurred preceding the impending locomotion. Interestingly, the M1 Ca2+ transients started ~100 ms earlier than that in V1. Furthermore, the population Ca2+ transients were robustly correlated with head movements. Thus, our work provides a simple but efficient approach for monitoring the cortical Ca2+ activity of a local cluster of neurons during locomotion in freely moving animals.

Ancient DNA reveals that the genetic structure of the northern Han Chinese was shaped prior to 3,000 years ago.

The Han Chinese are the largest ethnic group in the world, and their origins, development, and expansion are complex. Many genetic studies have shown that Han Chinese can be divided into two distinct groups: northern Han Chinese and southern Han Chinese. The genetic history of the southern Han Chinese has been well studied. However, the genetic history of the northern Han Chinese is still obscure. In order to gain insight into the genetic history of the northern Han Chinese, 89 human remains were sampled from the Hengbei site which is located in the Central Plain and dates back to a key transitional period during the rise of the Han Chinese (approximately 3,000 years ago). We used 64 authentic mtDNA data obtained in this study, 27 Y chromosome SNP data profiles from previously studied Hengbei samples, and genetic datasets of the current Chinese populations and two ancient northern Chinese populations to analyze the relationship between the ancient people of Hengbei and present-day northern Han Chinese. We used a wide range of population genetic analyses, including principal component analyses, shared mtDNA haplotype analyses, and geographic mapping of maternal genetic distances. The results show that the ancient people of Hengbei bore a strong genetic resemblance to present-day northern Han Chinese and were genetically distinct from other present-day Chinese populations and two ancient populations. These findings suggest that the genetic structure of northern Han Chinese was already shaped 3,000 years ago in the Central Plain area.

Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age.

BACKGROUND: The Tarim Basin, located on the ancient Silk Road, played a very important role in the history of human migration and cultural communications between the West and the East. However, both the exact period at which the relevant events occurred and the origins of the people in the area remain very obscure. In this paper, we present data from the analyses of both Y chromosomal and mitochondrial DNA (mtDNA) derived from human remains excavated from the Xiaohe cemetery, the oldest archeological site with human remains discovered in the Tarim Basin thus far. RESULTS: Mitochondrial DNA analysis showed that the Xiaohe people carried both the East Eurasian haplogroup (C) and the West Eurasian haplogroups (H and K), whereas Y chromosomal DNA analysis revealed only the West Eurasian haplogroup R1a1a in the male individuals. CONCLUSION: Our results demonstrated that the Xiaohe people were an admixture from populations originating from both the West and the East, implying that the Tarim Basin had been occupied by an admixed population since the early Bronze Age. To our knowledge, this is the earliest genetic evidence of an admixed population settled in the Tarim Basin.

Molecular genetic analysis of remains from Lamadong cemetery, Liaoning, China.

The Xianbei existed as a remarkable nomadic tribe in northeastern China for three dynasties: the Han, Jin, and Northern-Southern dynasties (206 BC to 581 AD) in Chinese history. A very important subtribe of the Xianbei is the Murong Xianbei. To investigate the genetic structure of the Murong Xianbei population and to address its genetic relationships with other nomadic tribes at a molecular level, we analyzed the control region sequences and coding-region single nucleotide polymorphism markers of mtDNA from the remains of the Lamadong cemetery of the Three-Yan Culture of the Murong Xianbei population, which is dated to 1,600-1,700 years ago. By combining polymorphisms of the control region with those from the code region, we assigned 17 individuals to haplogroups B, C, D, F, G2a, Z, M, and J1b1. The frequencies of these haplogroups were compared with those of Asian populations and a multidimensional scaling graph was constructed to investigate relationships with other Asian populations. The results indicate that the genetic structure of the Lamadong population is very intricate; it has haplogroups prevalent in both the Eastern Asian and the Siberian populations, showing more affinity with the Eastern Asian populations. The present study also shows that the ancient nomadic tribes of Huns, Tuoba Xianbei, and Murong Xianbei have different maternal genetic structures and that there could have been some genetic exchange among them.

Tracing the genetic history of the Chinese people: mitochondrial DNA analysis of aneolithic population from the Lajia site.

Ancient DNA analysis was conducted on the dental remains of specimens from the Lajia site, dating back 3,800-4,000 years. The Lajia site is located in Minhe county, Qinghai province, in northwestern China. Archaeological studies link Lajia to the late period of the Qijia culture, one of the most important Neolithic civilizations of the upper Yellow River region, the cradle of Chinese civilization. Excavations at the site revealed that the inhabitants died in their houses as the result of a sudden flood. The Lajia site provides a rare chance to study the putative families, all of whom died at the same instant. Possible maternal familial relationships were investigated through mitochondrial DNA (mtDNA) sequence analysis. Twelve sequences from individuals found in one house were assigned to only five haplotypes, consistent with a possible close kinship. Results from analyses of RFLP typing and HVI motifs suggest that the Lajia people belonged to the haplogroups B, C, D, M*, and M10. This study, combined with archaeological and anthropological investigations, provides a better understanding of the genetic history of the Chinese people.