Kinship and Deep History: Exploring Connections between Culture Areas, Genes, and Languages

Large-scale geographic variation in kinship systems may have deep roots. A number of authors now argue for an "emerging synthesis," with genetic, linguistic, and archeological findings coming together to paint a consistent picture of large-scale population spreads in prehistory. This article explores a social structural dimension of this synthesis: Major culture areas based on variation in kinship systems correspond closely—yet not perfectly—to genetic and linguistic clusters identified by other researchers. Thus it may be possible to reconstruct: (1) a set of "primary" culture areas corresponding to major population blocs and associated with ancient demic expansions and parallel transmission of genes and culture, and (2) a smaller set of overlying "secondary" culture areas of more recent origin that do not map onto genetic subdivisions and result from changes in subsistence or political economy independent of large-scale demic expansions. I also review latitudinal variation in kinship systems. [Keywords: culture areas, demic expansions, kinship (prehistory), protolanguages]     

Matrilocal residence is ancestral in Austronesian societies

The nature of social life in human prehistory is elusive, yet knowing how kinship systems evolve is critical for understanding population history and cultural diversity. Post-marital residence rules specify sex-specific dispersal and kin association, influencing the pattern of genetic markers across populations. Cultural phylogenetics allows us to practise ‘virtual archaeology’ on these aspects of social life that leave no trace in the archaeological record. Here we show that early Austronesian societies practised matrilocal post-marital residence. Using a Markov-chain Monte Carlo comparative method implemented in a Bayesian phylogenetic framework, we estimated the type of residence at each ancestral node in a sample of Austronesian language trees spanning 135 Pacific societies. Matrilocal residence has been hypothesized for proto-Oceanic society (ca 3500 BP), but we find strong evidence that matrilocality was predominant in earlier Austronesian societies ca 5000–4500 BP, at the root of the language family and its early branches. Our results illuminate the divergent patterns of mtDNA and Y-chromosome markers seen in the Pacific. The analysis of present-day cross-cultural data in this way allows us to directly address cultural evolutionary and life-history processes in prehistory.     

Mitochondrial origin of the matrilocal Mosuo people in China

The Mosuo people are currently the only matrilocal population in China. The origins of the population and their matrilocal tradition remain unknown. To address these questions, we studied the mitochondrial DNA (mtDNA) diversity of the Mosuo. Lower mtDNA diversity is expected in matrilocal populations because the women remain with their families after marriage, and there is generally less movement of mtDNA genomes in matrilocal populations. However, the haplotype diversity of this population is not lower than the neighboring patrilocal populations, indicating that the Mosuo started practicing matrilocality at least after the Paleolithic Age. A previous haplogroup frequency clustering study indicated that the Mosuo are closest to the Naxi people, but the network analysis of individual sequence haplotypes presented herein shows that most Mosuo lineages cluster with Pumi lineages. Therefore, we concluded that the Mosuo people have the closest genetic relationship with the Pumi, and that they started to practice matrilocality several thousand years ago.     

Where sociality and relatedness diverge: the genetic basis for hierarchical social organization in African elephants

Hierarchical properties characterize elephant fission–fusion social organization whereby stable groups of individuals coalesce into higher order groups or split in a predictable manner. This hierarchical complexity is rare among animals and, as such, an examination of the factors driving its emergence offers unique insight into the evolution of social behaviour. Investigation of the genetic basis for such social affiliation demonstrates that while the majority of core social groups (second-tier affiliates) are significantly related, this is not exclusively the case. As such, direct benefits received through membership of these groups appear to be salient to their formation and maintenance. Further analysis revealed that the majority of groups in the two higher social echelons (third and fourth tiers) are typically not significantly related. The majority of third-tier members are matrilocal, carrying the same mtDNA control region haplotype, while matrilocality among fourth-tier groups was slightly less than expected at random. Comparison of results to those from a less disturbed population suggests that human depredation, leading to social disruption, altered the genetic underpinning of social relations in the study population. These results suggest that inclusive fitness benefits may crystallize elephant hierarchical social structuring along genetic lines when populations are undisturbed. However, indirect benefits are not critical to the formation and maintenance of second-, third- or fourth-tier level bonds, indicating the importance of direct benefits in the emergence of complex, hierarchical social relations among elephants. Future directions and conservation implications are discussed.     

Demic and cultural diffusion in prehistoric Europe in the age of ancient genomes

Ancient genomes can help us detect prehistoric migrations, population contractions, and admixture among populations. Knowing the dynamics of demography is invaluable for understanding culture change in prehistory, particularly the roles played by demic and cultural diffusion in transformations of material cultures. Prehistoric Europe is a region where ancient genome analyses can help illuminate the interplay between demography and culture change. In Europe, there is more archeological evidence, in terms of detailed studies, radiometric dates, and explanatory hypotheses that can be evaluated, than in any other region of the world. Here I show some important ways that ancient genomes have given us insights into population movements in European prehistory. I also propose that studies might be increasingly focused on specific questions of culture change, for example in evaluating the makers of “transitional” industries as well as the origins of the Gravettian and spread of the Magdalenian. I also discuss genomic evidence supporting the large role that demic expansion has played in the Neolithization of Europe and the formation of the European population during the Bronze Age.     

Genetic variation in Northern Thailand Hill Tribes: origins and relationships with social structure and linguistic differences

Background

Ethnic minorities in Northern Thailand, often referred to as Hill Tribes, are considered an ideal model to study the different genetic impact of sex-specific migration rates expected in matrilocal (women remain in their natal villages after the marriage and men move to their wife's village) and patrilocal societies (the opposite is true). Previous studies identified such differences, but little is known about the possible interaction with another cultural factor that may potentially affect genetic diversity, i.e. linguistic differences. In addition, Hill Tribes started to migrate to Thailand in the last centuries from different Northern areas, but the history of these migrations, the level of genetic legacy with their places of origin, and the possible confounding effects related to this migration history in the patterns of genetic diversity, have not been analysed yet. Using both original and published data on the Hill Tribes and several other Asian populations, we focused on all these aspects.

Results

Genetic variation within population at mtDNA is lower in matrilocal, compared to patrilocal, tribes. The opposite is true for Y-chromosome microsatellites within the Sino-Tibetan linguistic family, but Hmong-Mien speaking patrilocal groups have a genetic diversity very similar to the matrilocal samples. Population divergence ranges between 5% and 14% at mtDNA sequences, and between 5% and 36% at Y- chromosomes STRs, and follows the sex-specific differences expected in patrilocal and matrilocal tribes. On the average, about 2 men and 14 women, and 4 men and 4 women, are exchanged in patrilocal and matrilocal tribes every generation, respectively. Most of the Hill Tribes in Thailand seem to preserve a genetic legacy with their likely geographic origin, with children adoption probably affecting this pattern in one tribe.

Conclusion

Overall, the sex specific genetic signature of different postmarital habits of residence in the Hill Tribes is robust. However, specific perturbations related to linguistic differences, population specific traits, and the complex migratory history of these groups, can be identified. Additional studies in different populations are needed, especially to obtain more precise estimates of the migration parameters.

     

Ice Ages and the mitochondrial DNA chronology of human dispersals: a review

Modern DNA, in particular maternally inherited mitochondrial DNA (mtDNA), is now routinely used to trace ancient human migration routes and to obtain absolute dates for genetic prehistory. The errors on absolute genetic dates are often large (50% or more) and depend partly on the inherent evolutionary signal in the DNA data, and partly on our imperfect knowledge of the DNA mutation rate. Despite their imprecision, the genetic dates do provide an independent, consistent and global chronology linking living humans with their ancestors. Combining this chronology with archaeological and climatological data, most of our own mtDNA studies during the past decade strongly imply a major role for palaeoclimate in determining conditions for prehistoric migrations and demographic expansions. This paper summarizes our interpretation of the genetic findings, covering the initial and modest spread of humans within Africa more than 100 ka, the striking re-expansion within Africa 60-80 ka, leading ultimately to the out-of-Africa migration of a single, small group which settled in Australia, Eurasia and America during windows of opportunity at least partly dictated by fluctuations in sea-levels and climatic conditions.     

The riddle of Tasmanian languages

Recent work which combines methods from linguistics and evolutionary biology has been fruitful in discovering the history of major language families because of similarities in evolutionary processes. Such work opens up new possibilities for language research on previously unsolvable problems, especially in areas where information from other sources may be lacking. I use phylogenetic methods to investigate Tasmanian languages. Existing materials are so fragmentary that scholars have been unable to discover how many languages are represented in the sources. Using a clustering algorithm which identifies admixture, source materials representing more than one language are identified. Using the Neighbor-Net algorithm, 12 languages are identified in five clusters. Bayesian phylogenetic methods reveal that the families are not demonstrably related; an important result, given the importance of Tasmanian Aborigines for information about how societies have responded to population collapse in prehistory. This work provides insight into the societies of prehistoric Tasmania and illustrates a new utility of phylogenetics in reconstructing linguistic history.     

Fine-scale population genetic structure in a fission-fusion society

Nonrandom patterns of mating and dispersal create fine-scale genetic structure in natural populations — especially of social mammals — with important evolutionary and conservation genetic consequences. Such structure is well-characterized for typical mammalian societies; that is, societies where social group composition is stable, dispersal is male-biased, and males form permanent breeding associations in just one or a few social groups over the course of their lives. However, genetic structure is not well understood for social mammals that differ from this pattern, including elephants. In elephant societies, social groups fission and fuse, and males never form permanent breeding associations with female groups. Here, we combine 33 years of behavioural observations with genetic information for 545 African elephants ( Loxodonta africana ), to investigate how mating and dispersal behaviours structure genetic variation between social groups and across age classes. We found that, like most social mammals, female matrilocality in elephants creates co-ancestry within core social groups and significant genetic differentiation between groups (Φ_ST = 0.058). However, unlike typical social mammals, male elephants do not bias reproduction towards a limited subset of social groups, and instead breed randomly across the population. As a result, reproductively dominant males mediate gene flow between core groups, which creates cohorts of similar-aged paternal relatives across the population. Because poaching tends to eliminate the oldest elephants from populations, illegal hunting and poaching are likely to erode fine-scale genetic structure. We discuss our results and their evolutionary and conservation genetic implications in the context of other social mammals.     

A social learning model of conflict and cooperation in human societies

Patterns of conflict and cooperation both within and between societies may be related to the degree of cultural similarity within and between the same societies. A simple model of social learning is used to predict patterns of conflict and cooperation in hypothetical societies that differ in the roles of relatives and nonrelatives in the enculturation of children. The model is illustrated by comparing its predictions to known differences in the patterns of conflict between males inpatrilocal and matrilocal societies.     

Reconstructing the history of marriage strategies in Indo-European-speaking societies: monogamy and polygyny

Explanations for the emergence of monogamous marriage have focused on the cross-cultural distribution of marriage strategies, thus failing to account for their history. In this paper I reconstruct the pattern of change in marriage strategies in the history of societies speaking Indo-European languages, using cross-cultural data in the systematic and explicitly historical framework afforded by the phylogenetic comparative approach. The analysis provides evidence in support of Proto-Indo-European monogamy, and that this pattern may have extended back to Proto-Indo-Hittite. These reconstructions push the origin of monogamous marriage into prehistory, well beyond the earliest instances documented in the historical record; this, in turn, challenges notions that the cross-cultural distribution of monogamous marriage reflects features of social organization typically associated with Eurasian societies, and with "societal complexity" and "modernization" more generally. I discuss implications of these findings in the context of the archaeological and genetic evidence on prehistoric social organization.     

On Cheyenne Sociopoutical Organization

Abstract

In a recent (1974) article John H. Moore has challenged the validity of earlier ethnologies of the Cheyenne Indians, with respect to their presentation of Cheyenne sociopolitical organization. Moore advances a dialectic model, positing matrilineal, matrilocal uterine bands from which were drawn the Peace Chiefs, who constituted a uterine tribal council. In frequent opposition, were the military societies, which Moore identifies as agnatic units of organization. Viewed historically, power shifted from the “uterine” bands and tribal council to the “agnatic” military societies.     

Bride‐service and the absent gift

Building on a previous experiment to apply Strathern's discussions of Melanesian gift exchange to ethnography relating to Tukanoan societies in Northwest Amazonia, this essay asks why other authors should repeatedly affirm that the gift has no relevance in the Amazonian context. Two answers are proposed. Firstly, the authors concerned tend to assume that a particular type of social formation is characteristic of Amazonia as a whole. The Tukanoans, who engage in ceremonial exchange of food and goods, do not fit this rubric. Secondly, despite their differences, these authors assume that Amazonian societies are bride‐service societies where, axiomatically, there can be no gift. The Tukanoans are not bride‐service societies and, if anything, tend towards the bride‐wealth alternative. This Tukanoan exception serves to re‐emphasize the diversity of Amazonian social formations, one that would have been even greater in the archaeological past. It also warns against the dangers of over‐hasty theoretical closure.     

Investigating sex-biased migration during the Neolithic transition in Europe, using an explicit spatial simulation framework

Cultural practices can deeply influence genetic diversity patterns. The Neolithic transitions that took place at different times and locations around the world led to major cultural and demographic changes that influenced and therefore left their marks on human genetic diversity patterns. Several studies on the European Neolithic transition suggest that mitochondrial DNA (mtDNA) and Y-chromosome data can exhibit different patterns, which could be owing to different demographic histories for females and males. Archaeological and anthropological data suggest that the transition from hunter-gatherers (HGs) to farmers' societies is probably associated with changes in social organization, particularly in post-marital residence (PMR) rules (i.e. patrilocality, matrilocality or bilocality). The movements of humans and genes associated with these rules can be seen as sex-biased short-range migrations. We developed a new individual-based simulation approach to explore the genetic consequences of 45 different scenarios, where we varied the patterns of PMR and admixture between HGs and farmers. We recorded mtDNA and Y-chromosome data and analysed their diversity patterns within and between populations, through time and space. We also collected published mtDNA and Y-chromosome data from European and Near-Eastern populations in order to identify the scenarios that would best explain them. We show that: (i) different PMR systems can lead to different patterns of genetic diversity and differentiation, (ii) asymmetries between mtDNA and Y-chromosome can be owing to different behaviours between males and females, but also to different mutations rates, and (iii) patrilocality in farmers explains the present patterns of genetic diversity better than matrilocality or bilocality. Moreover, we found that (iv) the genetic diversity of farmers change depending on the HGs PMR rules even though they are assumed to disappear more than 5000 years ago in our simulations.     

医学研究伦理学的发展现状与前景

创新技术的开展和转化医学的注重给医学的发展注入了新的活力,但同时,也带来了一系列社会伦理问题和法律问题。生命医学伦理学的兴起和发展催生了医学研究伦理学分支学科形成,目的在于推进解决涉及人体的医学研究的伦理问题。当前,面临的最突出的伦理问题在于,对医学研究合法性、先进性及伦理性的把握,对医学研究伦理审查必要性的认知,对医学研究方案设计与伦理道德的匹配,对医学研究知情同意的告知,对医学研究风险与受益的平衡。逐步与国际接轨,加强伦理委员会制度建设;提高伦理审查能力建设,形成高水平的伦理审查队伍;学术组织和团体共同努力,推进医学研究伦理学的发展,这将助推医学研究伦理学的发展。     

LIFE AT THE FRONT OF AN EXPANDING POPULATION

Environmental changes have caused episodes of habitat expansions in the evolutionary history of many species. These range changes affect the dynamics of biological evolution in multiple ways. Recent microbial experiments as well as simulations suggest that enhanced genetic drift at the frontier of a two-dimensional range expansion can cause genetic sectoring patterns with fractal domain boundaries. Here, we propose and analyze a simple model of asexual biological evolution at expanding frontiers that explains these neutral patterns and predicts the effect of natural selection. We find that beneficial mutations give rise to sectors with an opening angle that depends sensitively on the selective advantage of the mutants. Deleterious mutations, on the other hand, are not able to establish a sector permanently. They can, however, temporarily "surf" on the population front, and thereby reach unusually high frequencies. As a consequence, expanding frontiers are loaded with a high fraction of mutants at mutation–selection balance. Numerically, we also determine the condition at which the wild type is lost in favor of deleterious mutants (genetic meltdown) at a growing front. Our prediction for this error threshold differs qualitatively from existing well-mixed theories, and sets tight constraints on sustainable mutation rates for populations that undergo frequent range expansions.     

Policing effectiveness depends on relatedness and group size

Cohesion of social groups requires the suppression of individual selfishness. Indeed, worker egg laying in insect societies is usually suppressed or punished through aggression and egg removal. The effectiveness of such "policing" is expected to increase with decreasing relatedness, as inclusive fitness of group members is more strongly affected by selfish worker reproduction when group members are less closely related to each other. As inclusive fitness is also influenced by the costs and benefits of helping, the effectiveness of policing should decrease with increasing colony size, because the costs for the whole colony from selfish worker reproduction are proportionally reduced in large groups. Here, we show that policing effectiveness in colonies of the ant Temnothorax unifasciatus is low in large groups and high in small groups when relatedness is high. When we experimentally decreased the relatedness in groups, the policing effectiveness reached the same high level as in small, highly related groups, irrespective of group size. Therefore, our results indicate that policing effectiveness is simultaneously shaped by relatedness and group size, that is, an ecological factor. This may have major implications for testing policing across species of animals.     

Reply to Opler on Apachean Subsistence, Residence, and Girls' Puberty Rites

Archaeological evidence shows that Apaches occupied the central Plains area from A.D. 1525–1725 in Wyoming, South Dakota. Nebraska, Kansas, and Colorado. Toward the end of this period they were semi-sedentary farmers living in houses generically like those of the Plains-Prairies earth lodge. Because in their southward migration they contacted Plains-Prairies farmers earlier than those in the Southwest proper, and farming was women-dominated and residence matrilocal for the Hidatsa, Mandan, Arikara, Pawnee, and Wichita, it seems highly probable that these Plains Apaches acquired matrilocal residence and a female farming division of labor at this time before contacting Tanoans in the Southwest. The more western Apacheans, who may not have had contact with Plains tribes, could have acquired matrilocal residence from western Pueblos, including the Keresans, who were probably all matrilocal before Spanish contact. It is doubtful that the wild plant gathering of Apachean women was sufficient to cause matrilocal residence, because in parts of California and the Great Basin where women gathered a greater proportion of the diet than Apachean women, residence was vary rarely matrilocal.     

Complete mitochondrial genomes reveal neolithic expansion into Europe

The Neolithic transition from hunting and gathering to farming and cattle breeding marks one of the most drastic cultural changes in European prehistory. Short stretches of ancient mitochondrial DNA (mtDNA) from skeletons of pre-Neolithic hunter-gatherers as well as early Neolithic farmers support the demic diffusion model where a migration of early farmers from the Near East and a replacement of pre-Neolithic hunter-gatherers are largely responsible for cultural innovation and changes in subsistence strategies during the Neolithic revolution in Europe. In order to test if a signal of population expansion is still present in modern European mitochondrial DNA, we analyzed a comprehensive dataset of 1,151 complete mtDNAs from present-day Europeans. Relying upon ancient DNA data from previous investigations, we identified mtDNA haplogroups that are typical for early farmers and hunter-gatherers, namely H and U respectively. Bayesian skyline coalescence estimates were then used on subsets of complete mtDNAs from modern populations to look for signals of past population expansions. Our analyses revealed a population expansion between 15,000 and 10,000 years before present (YBP) in mtDNAs typical for hunters and gatherers, with a decline between 10,000 and 5,000 YBP. These corresponded to an analogous population increase approximately 9,000 YBP for mtDNAs typical of early farmers. The observed changes over time suggest that the spread of agriculture in Europe involved the expansion of farming populations into Europe followed by the eventual assimilation of resident hunter-gatherers. Our data show that contemporary mtDNA datasets can be used to study ancient population history if only limited ancient genetic data is available.     

Changes in Hidatsa Residence Patterns: a Cross-Cultural Interpretation

Abstract

Changes in Hidatsa marital residence patterns are described on the strength of ethnohistoric and ethnographic data. Such changes include a shift from a predominantly matrilocal to a multilocal pattern during the period 1780-1870. An interpretation for this change is offered in light of cross-cultural studies: multilocal residence is a response to depopulation due to infectious epidemic diseases in societies with some dependence on horticulture. A revision for the coding of Hidatsa marital residence in the Ethnographic Atlas is also suggested.