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Piqué-Fandiño L, Gallois S, Pavard S, Ramirez Rozzi FV. Reproductive seasonality in the Baka Pygmies, environmental factors and climatic changes. PLoS One 2022; 17:e0264761. [PMID: 35259192 PMCID: PMC8903253 DOI: 10.1371/journal.pone.0264761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 02/16/2022] [Indexed: 12/03/2022] Open
Abstract
Reproductive seasonality is a phenomenon common to human and animal populations and driven by, among others, climatic variables. Given the currently changing climate and its impacts on both the environment and human lives, the question arises of its potential effects on reproductive seasonality. Few studies have specifically explored the seasonality of reproduction among hunter-gatherers and anyone investigated how current climate change might affect this phenomenon. In this study we addressed reproductive seasonality in the Baka Pygmy living in African rain forests. Since reproductive seasonality can be linked to weather patterns, we explore this possibility. However, climatic variables driving weather patterns have changed over the years, so we assessed whether this has influenced the Baka reproductive pattern. Based on 34 years of written birth records and oral questionnaires from 13 years of systematic fieldwork, we observed a bimodal birth pattern with two birth peaks at 6-month intervals. Our results demonstrate that precipitation at conception or at birth potentially has effects, respectively negative and positive on the monthly number of births; and temperature has a role in controlling other variables that do affect the reproductive pattern. Changing weather patterns appear to be affecting the reproductive seasonality in the Baka, suggesting that attention needs to be given to the influence of global climate change on forager societies.
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Affiliation(s)
- Laura Piqué-Fandiño
- Eco-anthropologie (EA), Muséum national d’Histoire naturelle, CNRS, Université de Paris, Musée de l’Homme, Paris, France
| | | | - Samuel Pavard
- Eco-anthropologie (EA), Muséum national d’Histoire naturelle, CNRS, Université de Paris, Musée de l’Homme, Paris, France
| | - Fernando V. Ramirez Rozzi
- Eco-anthropologie (EA), Muséum national d’Histoire naturelle, CNRS, Université de Paris, Musée de l’Homme, Paris, France
- EA 2496, Faculté de Chirurgie Dentaire, Université de Paris, Montrouge, France
- * E-mail:
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Versluys TMM, Flintham EO, Mas-Sandoval A, Savolainen V. Why do we pick similar mates, or do we? Biol Lett 2021; 17:20210463. [PMID: 34813721 DOI: 10.1098/rsbl.2021.0463] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Humans often mate with those resembling themselves, a phenomenon described as positive assortative mating (PAM). The causes of this attract broad interest, but there is little agreement on the topic. This may be because empirical studies and reviews sometimes focus on just a few explanations, often based on disciplinary conventions. This review presents an interdisciplinary conceptual framework on the causes of PAM in humans, drawing on human and non-human biology, the social sciences, and the humanities. Viewing causality holistically, we first discuss the proximate causes (i.e. the 'how') of PAM, considering three mechanisms: stratification, convergence and mate choice. We also outline methods to control for confounders when studying mate choice. We then discuss ultimate explanations (i.e. 'the why') for PAM, including adaptive and non-adaptive processes. We conclude by suggesting a focus on interdisciplinarity in future research.
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Affiliation(s)
- Thomas M M Versluys
- Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, United Kingdom
| | - Ewan O Flintham
- Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, United Kingdom
| | - Alex Mas-Sandoval
- Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, United Kingdom
| | - Vincent Savolainen
- Georgina Mace Centre for the Living Planet, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, United Kingdom
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3
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Bouakaze C, Delehelle F, Saenz-Oyhéréguy N, Moreira A, Schiavinato S, Croze M, Delon S, Fortes-Lima C, Gibert M, Bujan L, Huyghe E, Bellis G, Calderon R, Hernández CL, Avendaño-Tamayo E, Bedoya G, Salas A, Mazières S, Charioni J, Migot-Nabias F, Ruiz-Linares A, Dugoujon JM, Thèves C, Mollereau-Manaute C, Noûs C, Poulet N, King T, D'Amato ME, Balaresque P. Predicting haplogroups using a versatile machine learning program (PredYMaLe) on a new mutationally balanced 32 Y-STR multiplex (CombYplex): Unlocking the full potential of the human STR mutation rate spectrum to estimate forensic parameters. Forensic Sci Int Genet 2020; 48:102342. [PMID: 32818722 DOI: 10.1016/j.fsigen.2020.102342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/24/2022]
Abstract
We developed a new mutationally well-balanced 32 Y-STR multiplex (CombYplex) together with a machine learning (ML) program PredYMaLe to assess the impact of STR mutability on haplogourp prediction, while respecting forensic community criteria (high DC/HD). We designed CombYplex around two sub-panels M1 and M2 characterized by average and high-mutation STR panels. Using these two sub-panels, we tested how our program PredYmale reacts to mutability when considering basal branches and, moving down, terminal branches. We tested first the discrimination capacity of CombYplex on 996 human samples using various forensic and statistical parameters and showed that its resolution is sufficient to separate haplogroup classes. In parallel, PredYMaLe was designed and used to test whether a ML approach can predict haplogroup classes from Y-STR profiles. Applied to our kit, SVM and Random Forest classifiers perform very well (average 97 %), better than Neural Network (average 91 %) and Bayesian methods (< 90 %). We observe heterogeneity in haplogroup assignation accuracy among classes, with most haplogroups having high prediction scores (99-100 %) and two (E1b1b and G) having lower scores (67 %). The small sample sizes of these classes explain the high tendency to misclassify the Y-profiles of these haplogroups; results were measurably improved as soon as more training data were added. We provide evidence that our ML approach is a robust method to accurately predict haplogroups when it is combined with a sufficient number of markers, well-balanced mutation rate Y-STR panels, and large ML training sets. Further research on confounding factors (such as CNV-STR or gene conversion) and ideal STR panels in regard to the branches analysed can be developed to help classifiers further optimize prediction scores.
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Affiliation(s)
- Caroline Bouakaze
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Franklin Delehelle
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France; REVA Unit, UMR 5505 - CNRS & Université de Toulouse, Institut de Recherche en Informatique de Toulouse, 31400 Toulouse, France
| | - Nancy Saenz-Oyhéréguy
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Andreia Moreira
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Stéphanie Schiavinato
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Myriam Croze
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Solène Delon
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Cesar Fortes-Lima
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Morgane Gibert
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Louis Bujan
- Equipe d'acceuil EA3694, Hôpital Paule de Viguier, 330 Avenue de Grande Bretagne, TSA 70034, 31059 Toulouse Cedex 9, France
| | - Eric Huyghe
- Equipe d'acceuil EA3694, Hôpital Paule de Viguier, 330 Avenue de Grande Bretagne, TSA 70034, 31059 Toulouse Cedex 9, France
| | - Gil Bellis
- INED Institut National d'Etudes Démographiques, 133 Boulevard Davout, 75980 Paris cedex 20, France
| | - Rosario Calderon
- Department of Biodiversity, Ecology and Evolution, Faculty of Biology, Complutense University. 28040 Madrid, Spain
| | - Candela Lucia Hernández
- Department of Biodiversity, Ecology and Evolution, Faculty of Biology, Complutense University. 28040 Madrid, Spain
| | - Efren Avendaño-Tamayo
- Grupo de Ciencias Básicas Aplicadas del Tecnológico de Antioquia, Tecnológico de Antioquia, Institución Universitaria, Medellín 050034, Colombia
| | - Gabriel Bedoya
- GENMOL (Genética Molecular), Instituto de Biología, Universidad de Antioquia Medellín Colombia, Colombia
| | - Antonio Salas
- Unidade de Xenética, Instituto de Ciencias Forenses (INCIFOR), Facultade de Medicina, Universidade de Santiago de Compostela, GenPoB Research Group, Instituto de Investigaciones, Sanitarias (IDIS), Hospital Clínico Universitario de Santiago (SERGAS), Galicia, Spain
| | | | - Jacques Charioni
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France; Etablissement Français du Sang PACA Corse, Marseille, France
| | | | - Andres Ruiz-Linares
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France; Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Jean-Michel Dugoujon
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Catherine Thèves
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Catherine Mollereau-Manaute
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France
| | - Camille Noûs
- Laboratoire Cogitamous, CNRS & Université Toulouse III, 31000 Toulouse, France
| | - Nicolas Poulet
- Pôle écohydraulique AFB-IMT, allée du Pr Camille Soula, 31400 Toulouse, France
| | - Turi King
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Maria Eugenia D'Amato
- Forensic DNA Laboratory, Department of Biotechnology, Faculty of Natural Sciences, University of Western Cape, Cape Town, South Africa
| | - Patricia Balaresque
- Laboratoire d´Anthropologie Moléculaire et Imagerie de Synthèse (AMIS), UMR5288 - CNRS & Université Toulouse III, 37 allées Jules Guesde, 31073 Toulouse Cedex 3, France.
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Abstract
The rapidly decreasing costs of generating genetic data sequencing and the ease of new DNA collection technologies have opened up new opportunities for anthropologists to conduct field-based genetic studies. An exciting aspect of this work comes from linking genetic data with the kinds of individual-level traits evolutionary anthropologists often rely on, such as those collected in long-term demographic and ethnographic studies. However, combining these two types of data raises a host of ethical questions related to the collection, analysis and reporting of such data. Here we address this conundrum by examining one particular case, the collection and analysis of paternity data. We are particularly interested in the logistics and ethics involved in genetic paternity testing in the localized settings where anthropologists often work. We discuss the particular issues related to paternity testing in these settings, including consent and disclosure, consideration of local identity and beliefs and developing a process of continued community engagement. We then present a case study of our own research in Namibia, where we developed a multi-tiered strategy for consent and community engagement, built around a double-blind procedure for data collection, analysis and reporting. Paternity testing in anthropology raises ethical and methodological issues. We summarize these and describe a novel double-blind method used in our work.
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Romero A, Ramirez-Rozzi FV, Cuesta-Torralvo E, Pérez-Pérez A. Age-related tooth wear in African rainforest hunter-gatherers. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 170:622-628. [PMID: 31599980 DOI: 10.1002/ajpa.23934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/01/2019] [Accepted: 09/11/2019] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Central African small-scale foragers subsist primarily on hunting game activities and wild plant-food gathering. Starch-rich tubers are underground storage organs (USOs) and staple food resources in savanna and tropical rainforests. However, little is known about the effect of USO consumption on tooth wear development in living hunter-gatherers. We report age- and sex-dependent tooth wear rates in forest-dwelling Baka Pygmies with well-documented wild-yam-tuber-based diet to explore the long-term impact of USO mechanical hardness and abrasiveness on the wearing down of the teeth. MATERIALS AND METHODS Percentages of dentine exposure (PDEs) of permanent left mandibular first molars (M1 ) were recorded using in vivo high-resolution replicas of Baka individuals (aged 8-33 years), inhabiting Le Bosquet district in Cameroon (Western Africa). Regression and covariance analyses were used to test the effect of individual aging by sex on PDE rates. RESULTS We found a strong increase of PDE by age among Baka individuals. No evidence of sexual dimorphism in wear patterns suggests similar sex-related dietary and masticatory demands during growth. Overall, greatest dentine exposure values ≈4% denote unexpected slow wear down rates for foraging diets relying on USO consumption. DISCUSSION The low molar wear rates with age found in Baka Pygmies contrast with extensive wear rates in savanna-dwelling foragers, reflecting differences in thermal processing techniques affecting fracture toughness and grittiness of mechanically challenging foods. Our findings reveal that culture-specific dietary proclivities influence tooth wear among foraging behaviors with important implications in hominin dietary versatility and abrasive stress on chewing surfaces.
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Affiliation(s)
- Alejandro Romero
- Departamento de Biotecnología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | | | - Elisabeth Cuesta-Torralvo
- Departament de Biologia Evolutiva, Ecologia i Ciencies Ambientals, Secció Zoologia i Antropologia Biològica, Universitat de Barcelona, Barcelona, Spain
| | - Alejandro Pérez-Pérez
- Departament de Biologia Evolutiva, Ecologia i Ciencies Ambientals, Secció Zoologia i Antropologia Biològica, Universitat de Barcelona, Barcelona, Spain
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6
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Romero A, Ramirez-Rozzi FV, Pérez-Pérez A. Dental size variability in Central African Pygmy hunter-gatherers and Bantu-speaking farmers. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:671-681. [PMID: 29566431 DOI: 10.1002/ajpa.23458] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 11/11/2022]
Abstract
OBJECTIVES Odontometric studies of African populations show high within-group variation in tooth size. Overall, North Africans exhibit smaller dimensions than groups from eastern and southern sub-Saharan regions, but no previous studies have analyzed the full dental metrics among extant African Pygmy hunter-gatherers and Bantu-speaking farmers. Furthermore, the population variability in tooth crown sizes from equatorial rainforest regions remains to be elucidated. MATERIALS AND METHODS The mesiodistal and buccolingual diameters of the permanent teeth (I1-M2) were measured in vivo using high-resolution replicas from Baka Pygmies and Mvae and Yassa Bantu-speakers from Cameroon (western Africa). Analyses of variance were used to record sex-related and population-level differences in tooth sizes, and a principal component analysis of geometrically scaled measures was used to plot the odontometric variability among groups. RESULTS Cameroonian Baka Pygmies differ in dental size from their Bantu-speaking neighbors. Molar teeth are larger in Pygmies than in Bantu individuals, while the anterior dentition is larger in the Bantu. Baka males exhibit significantly larger teeth than females, whereas sexual dimorphism in non-Pygmies is only present in the anterior dentition. DISCUSSION Odontometric patterns and the degree of sexual dimorphism in dental size differ among Central African groups, indicating adaptation to their different forager and farmer lifestyles. In particular, the admixture of Bantu-speakers in Baka populations is smaller than that in other western Pygmy groups. The greater dental phenetic diversity in Baka compared to that of the smaller-toothed farmers suggests that ecogenetic and microevolutionary factors are influencing a particular divergence scenario.
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Affiliation(s)
- Alejandro Romero
- Departamento de Biotecnología, Facultad de Ciencias, Universidad de Alicante, Alicante, 03080, Spain
| | | | - Alejandro Pérez-Pérez
- Departament de Biologia Evolutiva, Ecologia i Ciencies Ambientals, Secció Zoologia i Antropologia Biològica, Universitat de Barcelona, Barcelona, 08028, Spain
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Yost CL, Jackson LJ, Stone JR, Cohen AS. Subdecadal phytolith and charcoal records from Lake Malawi, East Africa imply minimal effects on human evolution from the ∼74 ka Toba supereruption. J Hum Evol 2018; 116:75-94. [PMID: 29477183 DOI: 10.1016/j.jhevol.2017.11.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/15/2017] [Accepted: 11/21/2017] [Indexed: 01/27/2023]
Abstract
The temporal proximity of the ∼74 ka Toba supereruption to a putative 100-50 ka human population bottleneck is the basis for the volcanic winter/weak Garden of Eden hypothesis, which states that the eruption caused a 6-year-long global volcanic winter and reduced the effective population of anatomically modern humans (AMH) to fewer than 10,000 individuals. To test this hypothesis, we sampled two cores collected from Lake Malawi with cryptotephra previously fingerprinted to the Toba supereruption. Phytolith and charcoal samples were continuously collected at ∼3-4 mm (∼8-9 yr) intervals above and below the Toba cryptotephra position, with no stratigraphic breaks. For samples synchronous or proximal to the Toba interval, we found no change in low elevation tree cover, or in cool climate C3 and warm season C4 xerophytic and mesophytic grass abundance that is outside of normal variability. A spike in locally derived charcoal and xerophytic C4 grasses immediately after the Toba eruption indicates reduced precipitation and die-off of at least some afromontane vegetation, but does not signal volcanic winter conditions. A review of Toba tuff petrological and melt inclusion studies suggest a Tambora-like 50 to 100 Mt SO2 atmospheric injection. However, most Toba climate models use SO2 values that are one to two orders of magnitude higher, thereby significantly overestimating the amount of cooling. A review of recent genetic studies finds no support for a genetic bottleneck at or near ∼74 ka. Based on these previous studies and our new paleoenvironmental data, we find no support for the Toba catastrophe hypothesis and conclude that the Toba supereruption did not 1) produce a 6-year-long volcanic winter in eastern Africa, 2) cause a genetic bottleneck among African AMH populations, or 3) bring humanity to the brink of extinction.
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Affiliation(s)
- Chad L Yost
- Department of Geosciences, University of Arizona, 1040 E 4th St., Tucson, AZ 85721, USA.
| | - Lily J Jackson
- Department of Geological Sciences, University of Texas at Austin, 2275 Speedway Stop C9000, Austin, TX 78712, USA
| | - Jeffery R Stone
- Department of Earth and Environmental Systems, Indiana State University, Terre Haute, IN 47809, USA
| | - Andrew S Cohen
- Department of Geosciences, University of Arizona, 1040 E 4th St., Tucson, AZ 85721, USA
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Genetic structure and invasion history of the house mouse (Mus musculus domesticus) in Senegal, West Africa: a legacy of colonial and contemporary times. Heredity (Edinb) 2017; 119:64-75. [PMID: 28353686 DOI: 10.1038/hdy.2017.18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 02/24/2017] [Accepted: 02/25/2017] [Indexed: 02/07/2023] Open
Abstract
Knowledge of the genetic make-up and demographic history of invasive populations is critical to understand invasion mechanisms. Commensal rodents are ideal models to study whether complex invasion histories are typical of introductions involving human activities. The house mouse Mus musculus domesticus is a major invasive synanthropic rodent originating from South-West Asia. It has been largely studied in Europe and on several remote islands, but the genetic structure and invasion history of this taxon have been little investigated in several continental areas, including West Africa. In this study, we focussed on invasive populations of M. m. domesticus in Senegal. In this focal area for European settlers, the distribution area and invasion spread of the house mouse is documented by decades of data on commensal rodent communities. Genetic variation at one mitochondrial locus and 16 nuclear microsatellite markers was analysed from individuals sampled in 36 sites distributed across the country. A combination of phylogeographic and population genetics methods showed that there was a single introduction event on the northern coast of Senegal, from an exogenous (probably West European) source, followed by a secondary introduction from northern Senegal into a coastal site further south. The geographic locations of these introduction sites were consistent with the colonial history of Senegal. Overall, the marked microsatellite genetic structure observed in Senegal, even between sites located close together, revealed a complex interplay of different demographic processes occurring during house mouse spatial expansion, including sequential founder effects and stratified dispersal due to human transport along major roads.
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Fort J. Demic and cultural diffusion propagated the Neolithic transition across different regions of Europe. J R Soc Interface 2016; 12. [PMID: 25977959 PMCID: PMC4424695 DOI: 10.1098/rsif.2015.0166] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The Neolithic transition is the shift from hunting–gathering into farming. About 9000 years ago, the Neolithic transition began to spread from the Near East into Europe, until it reached Northern Europe about 5500 years ago. There are two main models of this spread. The demic model assumes that it was mainly due to the reproduction and dispersal of farmers. The cultural model assumes that European hunter–gatherers become farmers by acquiring domestic plants and animals, as well as knowledge, from neighbouring farmers. Here we use the dates of about 900 archaeological sites to compute a speed map of the spread of the Neolithic transition in Europe. We compare the speed map to the speed ranges predicted by purely demic, demic–cultural and purely cultural models. The comparison indicates that the transition was cultural in Northern Europe, the Alpine region and west of the Black Sea. But demic diffusion was at work in other regions such as the Balkans and Central Europe. Our models can be applied to many other cultural traits. We also propose that genetic data could be gathered and used to measure the demic kernels of Early Neolithic populations. This would lead to an enormous advance in Neolithic spread modelling.
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Olivero J, Fa JE, Farfán MA, Lewis J, Hewlett B, Breuer T, Carpaneto GM, Fernández M, Germi F, Hattori S, Head J, Ichikawa M, Kitanaishi K, Knights J, Matsuura N, Migliano A, Nese B, Noss A, Ekoumou DO, Paulin P, Real R, Riddell M, Stevenson EGJ, Toda M, Vargas JM, Yasuoka H, Nasi R. Distribution and Numbers of Pygmies in Central African Forests. PLoS One 2016; 11:e0144499. [PMID: 26735953 PMCID: PMC4711706 DOI: 10.1371/journal.pone.0144499] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/19/2015] [Indexed: 12/04/2022] Open
Abstract
Pygmy populations occupy a vast territory extending west-to-east along the central African belt from the Congo Basin to Lake Victoria. However, their numbers and actual distribution is not known precisely. Here, we undertake this task by using locational data and population sizes for an unprecedented number of known Pygmy camps and settlements (n = 654) in five of the nine countries where currently distributed. With these data we develop spatial distribution models based on the favourability function, which distinguish areas with favourable environmental conditions from those less suitable for Pygmy presence. Highly favourable areas were significantly explained by presence of tropical forests, and by lower human pressure variables. For documented Pygmy settlements, we use the relationship between observed population sizes and predicted favourability values to estimate the total Pygmy population throughout Central Africa. We estimate that around 920,000 Pygmies (over 60% in DRC) is possible within favourable forest areas in Central Africa. We argue that fragmentation of the existing Pygmy populations, alongside pressure from extractive industries and sometimes conflict with conservation areas, endanger their future. There is an urgent need to inform policies that can mitigate against future external threats to these indigenous peoples’ culture and lifestyles.
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Affiliation(s)
- Jesús Olivero
- Grupo de Biogeografía, Diversidad y Conservación, Departamento de Biología Animal, Universidad de Málaga, Facultad de Ciencias, Málaga, Spain
| | - Julia E. Fa
- Division of Biology and Conservation Ecology, School of Science and the Environment, Manchester Metropolitan University, Manchester, United Kingdom
- Center for International Forestry Research (CIFOR), CIFOR Headquarters, Bogor, Indonesia
- * E-mail:
| | - Miguel A. Farfán
- Grupo de Biogeografía, Diversidad y Conservación, Departamento de Biología Animal, Universidad de Málaga, Facultad de Ciencias, Málaga, Spain
| | - Jerome Lewis
- Department of Anthropology, University College London, London, United Kingdom
| | - Barry Hewlett
- Department of Anthropology, Washington State University, Vancouver, Washington, United States of America
| | - Thomas Breuer
- Global Conservation Program, Wildlife Conservation Society, Bronx, New York, United States of America
| | | | | | | | - Shiho Hattori
- Faculty of International Studies, Tenri University, Tenri City, Nara, Japan
| | | | | | - Koichi Kitanaishi
- Faculty of Education, Yamaguchi University, Yoshida, Yamaguchi-shi Yamaguchi, Japan
| | - Jessica Knights
- Department of Anthropology, University College London, London, United Kingdom
| | - Naoki Matsuura
- Graduate School of Asian and African Area Studies, Kyoto University, Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto, Japan
| | - Andrea Migliano
- Department of Anthropology, University College London, London, United Kingdom
| | - Barbara Nese
- COOPI-Cooperazione Internazionale ONG Onlus, Milano–I, Italy
| | - Andrew Noss
- Department of Geography, University of Florida, Gainesville, Florida, United States of America
| | | | | | - Raimundo Real
- Grupo de Biogeografía, Diversidad y Conservación, Departamento de Biología Animal, Universidad de Málaga, Facultad de Ciencias, Málaga, Spain
| | - Mike Riddell
- Bioclimate, Research and Development, Edinburgh, United Kingdom
| | | | - Mikako Toda
- Graduate School of Asian and African Area Studies, Kyoto University, Shimoadachi-cho, Yoshida, Sakyo-ku, Kyoto, Japan
| | - J. Mario Vargas
- Grupo de Biogeografía, Diversidad y Conservación, Departamento de Biología Animal, Universidad de Málaga, Facultad de Ciencias, Málaga, Spain
| | - Hirokazu Yasuoka
- Faculty of Humanity and Environment, Hosei University, Fujimi, Chiyoda-ku, Tokyo, Japan
| | - Robert Nasi
- Consultative Group on International Agricultural Research (CGIAR), CIFOR Headquarters, Jalan CIFOR, Situ Gede, Bogor, Indonesia
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Romero A, Ramírez-Rozzi FV, De Juan J, Pérez-Pérez A. Diet-related buccal dental microwear patterns in Central African Pygmy foragers and Bantu-speaking farmer and pastoralist populations. PLoS One 2013; 8:e84804. [PMID: 24367696 PMCID: PMC3868657 DOI: 10.1371/journal.pone.0084804] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/19/2013] [Indexed: 12/03/2022] Open
Abstract
Pygmy hunter-gatherers from Central Africa have shared a network of socioeconomic interactions with non-Pygmy Bantu speakers since agropastoral lifestyle spread across sub-Saharan Africa. Ethnographic studies have reported that their diets differ in consumption of both animal proteins and starch grains. Hunted meat and gathered plant foods, especially underground storage organs (USOs), are dietary staples for pygmies. However, scarce information exists about forager–farmer interaction and the agricultural products used by pygmies. Since the effects of dietary preferences on teeth in modern and past pygmies remain unknown, we explored dietary history through quantitative analysis of buccal microwear on cheek teeth in well-documented Baka pygmies. We then determined if microwear patterns differ among other Pygmy groups (Aka, Mbuti, and Babongo) and between Bantu-speaking farmer and pastoralist populations from past centuries. The buccal dental microwear patterns of Pygmy hunter-gatherers and non-Pygmy Bantu pastoralists show lower scratch densities, indicative of diets more intensively based on nonabrasive foodstuffs, compared with Bantu farmers, who consume larger amounts of grit from stoneground foods. The Baka pygmies showed microwear patterns similar to those of ancient Aka and Mbuti, suggesting that the mechanical properties of their preferred diets have not significantly changed through time. In contrast, Babongo pygmies showed scratch densities and lengths similar to those of the farmers, consistent with sociocultural contacts and genetic factors. Our findings support that buccal microwear patterns predict dietary habits independent of ecological conditions and reflect the abrasive properties of preferred or fallback foods such as USOs, which may have contributed to the dietary specializations of ancient human populations.
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Affiliation(s)
- Alejandro Romero
- Universidad de Alicante, Departamento de Biotecnología, Alicante, Spain
| | - Fernando V. Ramírez-Rozzi
- Centre National de la Recherche Scientifique, Unité Propre de Recherche “Dynamique de l’Évolution Humaine,” Paris, France
| | - Joaquín De Juan
- Universidad de Alicante, Departamento de Biotecnología, Alicante, Spain
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Verdu P, Becker NSA, Froment A, Georges M, Grugni V, Quintana-Murci L, Hombert JM, Van der Veen L, Le Bomin S, Bahuchet S, Heyer E, Austerlitz F. Sociocultural behavior, sex-biased admixture, and effective population sizes in Central African Pygmies and non-Pygmies. Mol Biol Evol 2013; 30:918-37. [PMID: 23300254 DOI: 10.1093/molbev/mss328] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sociocultural phenomena, such as exogamy or phylopatry, can largely determine human sex-specific demography. In Central Africa, diverging patterns of sex-specific genetic variation have been observed between mobile hunter-gatherer Pygmies and sedentary agricultural non-Pygmies. However, their sex-specific demography remains largely unknown. Using population genetics and approximate Bayesian computation approaches, we inferred male and female effective population sizes, sex-specific migration, and admixture rates in 23 Central African Pygmy and non-Pygmy populations, genotyped for autosomal, X-linked, Y-linked, and mitochondrial markers. We found much larger effective population sizes and migration rates among non-Pygmy populations than among Pygmies, in agreement with the recent expansions and migrations of non-Pygmies and, conversely, the isolation and stationary demography of Pygmy groups. We found larger effective sizes and migration rates for males than for females for Pygmies, and vice versa for non-Pygmies. Thus, although most Pygmy populations have patrilocal customs, their sex-specific genetic patterns resemble those of matrilocal populations. In fact, our results are consistent with a lower prevalence of polygyny and patrilocality in Pygmies compared with non-Pygmies and a potential female transmission of reproductive success in Pygmies. Finally, Pygmy populations showed variable admixture levels with the non-Pygmies, with often much larger introgression from male than from female lineages. Social discrimination against Pygmies triggering complex movements of spouses in intermarriages can explain these male-biased admixture patterns in a patrilocal context. We show how gender-related sociocultural phenomena can determine highly variable sex-specific demography among populations, and how population genetic approaches contrasting chromosomal types allow inferring detailed human sex-specific demographic history.
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Affiliation(s)
- Paul Verdu
- Department of Biology, Stanford University, USA.
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Abstract
Genetic and paleoanthropological evidence is in accord that today's human population is the result of a great demic (demographic and geographic) expansion that began approximately 45,000 to 60,000 y ago in Africa and rapidly resulted in human occupation of almost all of the Earth's habitable regions. Genomic data from contemporary humans suggest that this expansion was accompanied by a continuous loss of genetic diversity, a result of what is called the "serial founder effect." In addition to genomic data, the serial founder effect model is now supported by the genetics of human parasites, morphology, and linguistics. This particular population history gave rise to the two defining features of genetic variation in humans: genomes from the substructured populations of Africa retain an exceptional number of unique variants, and there is a dramatic reduction in genetic diversity within populations living outside of Africa. These two patterns are relevant for medical genetic studies mapping genotypes to phenotypes and for inferring the power of natural selection in human history. It should be appreciated that the initial expansion and subsequent serial founder effect were determined by demographic and sociocultural factors associated with hunter-gatherer populations. How do we reconcile this major demic expansion with the population stability that followed for thousands years until the inventions of agriculture? We review advances in understanding the genetic diversity within Africa and the great human expansion out of Africa and offer hypotheses that can help to establish a more synthetic view of modern human evolution.
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