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1.
Proc Natl Acad Sci U S A ; 121(9): e2318181121, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38346210

RESUMO

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence.


Assuntos
Economia , Fertilidade , Feminino , Humanos , Dinâmica Populacional , Fatores Socioeconômicos , Países em Desenvolvimento
2.
Nature ; 538(7624): 207-214, 2016 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-27654914

RESUMO

The population history of Aboriginal Australians remains largely uncharacterized. Here we generate high-coverage genomes for 83 Aboriginal Australians (speakers of Pama-Nyungan languages) and 25 Papuans from the New Guinea Highlands. We find that Papuan and Aboriginal Australian ancestors diversified 25-40 thousand years ago (kya), suggesting pre-Holocene population structure in the ancient continent of Sahul (Australia, New Guinea and Tasmania). However, all of the studied Aboriginal Australians descend from a single founding population that differentiated ~10-32 kya. We infer a population expansion in northeast Australia during the Holocene epoch (past 10,000 years) associated with limited gene flow from this region to the rest of Australia, consistent with the spread of the Pama-Nyungan languages. We estimate that Aboriginal Australians and Papuans diverged from Eurasians 51-72 kya, following a single out-of-Africa dispersal, and subsequently admixed with archaic populations. Finally, we report evidence of selection in Aboriginal Australians potentially associated with living in the desert.


Assuntos
Genoma Humano/genética , Genômica , Havaiano Nativo ou Outro Ilhéu do Pacífico/genética , Filogenia , Grupos Raciais/genética , África/etnologia , Austrália , Conjuntos de Dados como Assunto , Clima Desértico , Fluxo Gênico , Genética Populacional , História Antiga , Migração Humana/história , Humanos , Idioma , Nova Guiné , Dinâmica Populacional , Tasmânia
3.
Evol Hum Sci ; 6: e11, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38516373

RESUMO

Among vertebrates, allomothering (non-maternal care) is classified as cooperative breeding (help from sexually mature non-breeders, usually close relatives) or communal breeding (shared care between multiple breeders who are not necessarily related). Humans have been described with both labels, most frequently as cooperative breeders. However, few studies have quantified the relative contributions of allomothers according to whether they are (a) sexually mature and reproductively active and (b) related or unrelated. We constructed close-proximity networks of Agta and BaYaka hunter-gatherers. We used portable remote-sensing devices to quantify the proportion of time children under the age of 4 spent in close proximity to different categories of potential allomother. Both related and unrelated, and reproductively active and inactive, campmates had substantial involvement in children's close-proximity networks. Unrelated campmates, siblings and subadults were the most involved in both populations, whereas the involvement of fathers and grandmothers was the most variable between the two populations. Finally, the involvement of sexually mature, reproductively inactive adults was low. Where possible, we compared our findings with studies of other hunter-gatherer societies, and observed numerous consistent trends. Based on our results we discuss why hunter-gatherer allomothering cannot be fully characterised as cooperative or communal breeding.

4.
Philos Trans R Soc Lond B Biol Sci ; 378(1868): 20210435, 2023 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-36440566

RESUMO

Women cooperate over multiple domains and while research from western contexts portrays women's networks as limited in size and breadth, women receive help, particularly with childcare, from a diverse range of individuals (allomothers). Nonetheless, little exploration has occurred into why we see such diversity. Wide maternal childcare networks may be a consequence of a lack of resource accumulation in mobile hunter-gatherers-where instead households rely on risk-pooling in informal insurance networks. By contrast, when households settle and accumulate resources, they are able to retain risk by absorbing losses. Thus, the size and composition of mothers' childcare networks may depend on risk-buffering, as captured by mobile and settled households in the Agta, a Philippine foraging population with diverse lifestyles. Across 78 children, we find that childcare from grandmothers and sisters was higher in settled camps, while childcare from male kin was lower, offering little support for risk-buffering. Nonetheless, girls' workloads were increased in settled camps while grandmothers had fewer dependent children, increasing their availability. These results point to gender-specific changes associated with shifting demographics as camps become larger and more settled. Evidently, women's social networks, rather than being constrained by biology, are responsive to the changing socioecological context. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.


Assuntos
Cuidado da Criança , Avós , Criança , Humanos , Masculino , Feminino , Saúde da Criança , Mães , Características da Família
5.
Evol Med Public Health ; 11(1): 149-162, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37274122

RESUMO

Background and objectives: There is significant evidence from large-scale, industrial and post-industrial societies that greater income and wealth inequality is negatively associated with both population health and increasing health inequalities. However, whether such relationships are inevitable and should be expected to impact the health of small-scale societies as they become more market-integrated is less clear. Methodology: Here, using mixed-effect models, we explore the relationship between health, wealth, wealth inequality and health inequalities in a small-scale foraging population from the Philippines, the Agta. Results: Across 11 camps, we find small to moderate degrees of wealth inequality (maximal Gini Coefficient 0.44) which is highest in the most permanent camps, where individuals engage more heavily in the formal market. However, in both adults (n = 161) and children (n = 215), we find little evidence that either wealth or wealth inequality associates with ill health, except for one measure of nutritional condition-red blood cell count. Conclusions and implications: We interpret these results in the light of high levels of cooperation among the Agta which may buffer against the detrimental effects of wealth inequality documented in industrial and post-industrial societies. We observe little intergenerational wealth transmission, highlighting the fluid nature of wealth, and thus wealth inequality, particularly in mobile communities. The deterioration of nutritional status, as indicated by red blood cell counts, requires further investigation before concluding the Agta's extensive cooperation networks may be beginning to breakdown in the face of increasing inequality.

6.
PLoS One ; 18(4): e0284360, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37099506

RESUMO

Examining development is essential for a full understanding of behaviour, including how individuals acquire traits and how adaptive evolutionary forces shape these processes. The present study explores the development of cooperative behaviour among the Agta, a Filipino hunter-gatherer population. A simple resource allocation game assessing both levels of cooperation (how much children shared) and patterns of partner choice (who they shared with) was played with 179 children between the ages of 3 and 18. Children were given five resources (candies) and for each was asked whether to keep it for themselves or share with someone else, and if so, who this was. Between-camp variation in children's cooperative behaviour was substantial, and the only strong predictor of children's cooperation was the average level of cooperation among adults in camp; that is, children were more cooperative in camps where adults were more cooperative. Neither age, sex, relatedness or parental levels of cooperation were strongly associated with the amount children shared. Children preferentially shared with close kin (especially siblings), although older children increasingly shared with less-related individuals. Findings are discussed in terms of their implications for understanding cross-cultural patterns of children's cooperation, and broader links with human cooperative childcare and life history evolution.


Assuntos
Acampamento , Comportamento Cooperativo , Adolescente , Adulto , Criança , Pré-Escolar , Humanos , Povo Asiático , Saúde da Criança , Irmãos
7.
Evol Hum Sci ; 5: e13, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37587941

RESUMO

Ecological and genetic factors have influenced the composition of the human microbiome during our evolutionary history. We analysed the oral microbiota of the Agta, a hunter-gatherer population where some members have adopted an agricultural diet. We show that age is the strongest factor modulating the microbiome, probably through immunosenescence since we identified an increase in the number of species classified as pathogens with age. We also characterised biological and cultural processes generating sexual dimorphism in the oral microbiome. A small subset of oral bacteria is influenced by the host genome, linking host collagen genes to bacterial biofilm formation. Our data also suggest that shifting from a fish/meat diet to a rice-rich diet transforms their microbiome, mirroring the Neolithic transition. All of these factors have implications in the epidemiology of oral diseases. Thus, the human oral microbiome is multifactorial and shaped by various ecological and social factors that modify the oral environment.

8.
PNAS Nexus ; 1(4): pgac168, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36714869

RESUMO

Human hypercooperativity and the emergence of division of labor enables us to solve problems not only effectively within a group but also collectively. Collective problem-solving occurs when groups perform better than the additive performance of separate individuals. Currently, it is unknown whether this is unique to humans. To investigate the evolutionary origin of collective problem-solving and potential precursors, we propose a continuum of group effects on problem-solving, from simple to complex ones, eventually culminating in collective problem-solving. We tested captive common marmosets with a series of problem-solving tasks, either alone or in a group. To test whether the performance of a group was more than the sum of its parts, we compared real groups to virtual groups (pooled scores of animals tested alone). Marmosets in real groups were both more likely to solve problems than marmosets within the virtual groups and to do so faster. Although individuals within real groups approached the problem faster, a reduction in neophobia was not sufficient to explain the greater success. Success within real groups arose because animals showed higher perseverance, especially after a fellow group member had found the solution in complex tasks. These results are consistent with the idea that group problem-solving evolved alongside a continuum, with performance improving beyond baseline as societies move from social tolerance to opportunities for diffusion of information to active exchange of information. We suggest that increasing interdependence and the adoption of cooperative breeding pushed our ancestors up this scale.

9.
Philos Trans R Soc Lond B Biol Sci ; 376(1827): 20200026, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-33938270

RESUMO

Non-maternal carers (allomothers) are hypothesized to lighten the mother's workload, allowing for the specialized human life history including relatively short interbirth intervals and multiple dependent offspring. Here, using in-depth observational data on childcare provided to 78 Agta children (a foraging population in the northern Philippines; aged 0-6 years), we explore whether allomaternal childcare substitutes and decreases maternal childcare. We found that allomother caregiving was associated with reduced maternal childcare, but the substitutive effect varied depending on the source and type of care. Children-only playgroups consistently predicted a decrease in maternal childcare. While grandmothers were rarely available, their presence was negatively associated with maternal presence and childcare, and grandmothers performed similar childcare activities to mothers. These results underscore the importance of allomothering in reducing maternal childcare in the Agta. Our findings suggest that flexibility in childcare sources, including children-only playgroups, may have been the key to human life-history evolution. Overall, our results reinforce the necessity of a broad conceptualization of social support in human childcare. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.


Assuntos
Cuidado da Criança , Comportamento Cooperativo , Mães , Poder Familiar , Apoio Social , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Mães/psicologia , Mães/estatística & dados numéricos , Filipinas , Jogos e Brinquedos
10.
Sci Rep ; 11(1): 23070, 2021 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-34845256

RESUMO

HLA-G is a promiscuous immune checkpoint molecule. The HLA-G gene presents substantial nucleotide variability in its regulatory regions. However, it encodes a limited number of proteins compared to classical HLA class I genes. We characterized the HLA-G genetic variability in 4640 individuals from 88 different population samples across the globe by using a state-of-the-art method to characterize polymorphisms and haplotypes from high-coverage next-generation sequencing data. We also provide insights regarding the HLA-G genetic diversity and a resource for future studies evaluating HLA-G polymorphisms in different populations and association studies. Despite the great haplotype variability, we demonstrated that: (1) most of the HLA-G polymorphisms are in introns and regulatory sequences, and these are the sites with evidence of balancing selection, (2) linkage disequilibrium is high throughout the gene, extending up to HLA-A, (3) there are few proteins frequently observed in worldwide populations, with lack of variation in residues associated with major HLA-G biological properties (dimer formation, interaction with leukocyte receptors). These observations corroborate the role of HLA-G as an immune checkpoint molecule rather than as an antigen-presenting molecule. Understanding HLA-G variability across populations is relevant for disease association and functional studies.


Assuntos
Antígenos HLA-G/genética , Polimorfismo Genético , Regiões 3' não Traduzidas , Alelos , Biologia Computacional , Dimerização , Evolução Molecular , Frequência do Gene , Genes MHC Classe I , Variação Genética , Genética Populacional , Genótipo , Saúde Global , Haplótipos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Proteínas de Checkpoint Imunológico/genética , Imunogenética , Íntrons , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único
11.
Sci Adv ; 6(9): eaax5913, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32158935

RESUMO

Although multilevel sociality is a universal feature of human social organization, its functional relevance remains unclear. Here, we investigated the effect of multilevel sociality on cumulative cultural evolution by using wireless sensing technology to map inter- and intraband social networks among Agta hunter-gatherers. By simulating the accumulation of cultural innovations over the real Agta multicamp networks, we demonstrate that multilevel sociality accelerates cultural differentiation and cumulative cultural evolution. Our results suggest that hunter-gatherer social structures [based on (i) clustering of families within camps and camps within regions, (ii) cultural transmission within kinship networks, and (iii) high intercamp mobility] may have allowed past and present hunter-gatherers to maintain cumulative cultural adaptation despite low population density, a feature that may have been critical in facilitating the global expansion of Homo sapiens.


Assuntos
Evolução Cultural , Comportamento Social , Humanos
12.
Nat Hum Behav ; 3(11): 1154-1163, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31406338

RESUMO

Human children are frequently cared for by non-parental caregivers (alloparents), yet few studies have conducted systematic alternative hypothesis tests of why alloparents help. Here we explore whether predictions from kin selection, reciprocity, learning-to-mother and costly signalling hypotheses explain non-parental childcare among Agta hunter-gatherers from the Philippines. To test these hypotheses, we used high-resolution proximity data from 1,701 child-alloparent dyads. Our results indicated that reciprocity and relatedness were positively associated with the number of interactions with a child (our proxy for childcare). Need appeared more influential in close kin, suggesting indirect benefits, while reciprocity proved to be a stronger influence in non-kin, pointing to direct benefits. However, despite shared genes, close and distant kin interactions were also contingent on reciprocity. Compared with other apes, humans are unique in rapidly producing energetically demanding offspring. Our results suggest that the support that mothers require is met through support based on kinship and reciprocity.


Assuntos
Cuidadores , Cuidado da Criança , Poder Familiar , Pais , Adolescente , Adulto , Idoso , Antropologia Cultural , Criança , Pré-Escolar , Comportamento Cooperativo , Família , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Filipinas , Comportamento Social , Adulto Jovem
13.
Science ; 334(6052): 94-8, 2011 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21940856

RESUMO

We present an Aboriginal Australian genomic sequence obtained from a 100-year-old lock of hair donated by an Aboriginal man from southern Western Australia in the early 20th century. We detect no evidence of European admixture and estimate contamination levels to be below 0.5%. We show that Aboriginal Australians are descendants of an early human dispersal into eastern Asia, possibly 62,000 to 75,000 years ago. This dispersal is separate from the one that gave rise to modern Asians 25,000 to 38,000 years ago. We also find evidence of gene flow between populations of the two dispersal waves prior to the divergence of Native Americans from modern Asian ancestors. Our findings support the hypothesis that present-day Aboriginal Australians descend from the earliest humans to occupy Australia, likely representing one of the oldest continuous populations outside Africa.


Assuntos
Genoma Humano , Havaiano Nativo ou Outro Ilhéu do Pacífico/genética , Animais , Ásia , Povo Asiático/genética , População Negra , Simulação por Computador , DNA Mitocondrial/genética , Emigração e Imigração , Etnicidade/genética , Ásia Oriental , Fluxo Gênico , Frequência do Gene , Genética Populacional/métodos , Genoma Mitocondrial , Haplótipos , Hominidae/genética , Humanos , Desequilíbrio de Ligação , Masculino , Filogenia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Austrália Ocidental , População Branca/genética
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