Human culture, biology, and health were shaped dramatically by the onset of agriculture ~12,000 y... more Human culture, biology, and health were shaped dramatically by the onset of agriculture ~12,000 years before present (BP). Subsistence shifts from hunting and gathering to agriculture are hypothesized to have resulted in increased individual fitness and population growth as evidenced by archaeological and population genomic data alongside a simultaneous decline in physiological health as inferred from paleopathological analyses and stature reconstructions of skeletal remains. A key component of the health decline inference is that relatively shorter statures observed for early farmers may (at least partly) reflect higher childhood disease burdens and poorer nutrition. However, while such stresses can indeed result in growth stunting, height is also highly heritable, and substantial inter-individual variation in the height genetic component within a population is typical. Moreover, extensive migration and gene flow were characteristics of multiple agricultural transitions worldwide. ...
OBJECTIVES Magnitudes of morphological integration may constrain or facilitate craniofacial shape... more OBJECTIVES Magnitudes of morphological integration may constrain or facilitate craniofacial shape variation. The aim of this study was to analyze how the magnitude of integration in the skull of Macaca fascicularis changes throughout ontogeny in relation to developmental and/or functional modules. MATERIALS AND METHODS Geometric morphometric methods were used to analyze the magnitude of integration in the macaque cranium and mandible in 80 juvenile and 40 adult M. fascicularis specimens. Integration scores in skull modules were calculated using integration coefficient of variation (ICV) of eigenvalues based on a resampling procedure. Resultant ICV scores between the skull as a whole, and developmental and/or functional modules were compared using Mann-Whitney U tests. RESULTS Results showed that most skull modules were more tightly integrated than the skull as a whole, with the exception of the chondrocranium in juveniles without canines, the chondrocranium/face complex and the mandibular corpus in adults, and the mandibular ramus in all juveniles. The chondrocranium/face and face/mandibular corpus complexes were more tightly integrated in juveniles than adults, possibly reflecting the influences of early brain growth/development, and the changing functional demands of infant suckling and later masticatory loading. This is also supported by the much higher integration of the mandibular ramus in adults compared with juveniles. DISCUSSION Magnitudes of integration in skull modules reflect developmental/functional mechanisms in M. fascicularis. However, the relationship between "evolutionary flexibility" and developmental/functional mechanisms was not direct or simple, likely because of the complex morphology, multifunctionality, and various ossification origins of the skull.
The human settlement of the Americas has been a topic of intense debate for centuries, and there ... more The human settlement of the Americas has been a topic of intense debate for centuries, and there is still no consensus on the tempo and mode of early human dispersion across the continent. When trying to explain the biological diversity of early groups across North, Central and South America, studies have defended a wide range of dispersion models that tend to oversimplify the diversity observed across the continent. In this study, we aim to contribute to this debate by exploring the cranial morphological affinities of four late Pleistocene/early Holocene specimens recovered from the caves of Quintana Roo, Mexico. The four specimens are among the earliest human remains known in the continent and permit the contextualization of biological diversity present during the initial millennia of human presence in the Americas. The specimens were compared to worldwide reference series through geometric morphometric analyses of 3D anatomical landmarks. Morphological data were analyzed through ...
Objectives: This study analyzes craniofacial shape variation in the Hehuang region of Northwest C... more 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 F ST 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. K E Y W O R D S 3D geometric morphometrics, Hehuang region, population history, skull morphology
Hominoid cranial evolution is characterized by substantial phenotypic diversity, yet the cause of... more Hominoid cranial evolution is characterized by substantial phenotypic diversity, yet the cause of this variability has rarely been explored. Quantitative genetic techniques for investigating evolutionary processes underlying morphological divergence are dependent on the availability of good ancestral models, a problem in hominoids where the fossil record is fragmentary and poorly understood. Here, we use a maximum likelihood approach based on a Brownian motion model of evolutionary change to estimate nested hypothetical ancestral forms from 15 extant hominoid taxa. These ancestors were then used to calculate rates of evolution along each branch of a phylogenetic tree using Lande's generalized genetic distance. Our results show that hominoid cranial evolution is characterized by strong stabilizing selection. Only two instances of directional selection were detected; the divergence of Homo from its last common ancestor with Pan, and the divergence of the lesser apes from their last common ancestor with the great apes. In these two cases, selection gradients reconstructed to identify the specific traits undergoing selection indicated that selection on basicranial flexion, cranial vault expansion and facial retraction characterizes the divergence of Homo, whereas the divergence of the lesser apes was defined by selection on neurocranial size reduction. This article is protected by copyright. All rights reserved.
American journal of physical anthropology, Jan 27, 2017
Debate persists regarding the biological makeup of European Ottoman communities settled during th... more Debate persists regarding the biological makeup of European Ottoman communities settled during the expansion of the Ottoman Empire during the 16th and 17th centuries, and the roles of conversion and migration in shaping demography and population history. The aim of this study was to perform an assessment of the biological affinities of three European Ottoman series based on craniometric data. Craniometric data collected from three Ottoman series from Hungary and Romania were compared to European and Anatolian comparative series, selected to represent biological affinity representative of historically recorded migration and conversion influences. Sex-separated samples were analyzed using D(2) -matrices, along with principal coordinates and PERMANOVA analyses to investigate biological affinities. Discriminant function analysis was employed to assign Ottoman individuals to two potential classes: European or Anatolian. Affinity analyses show larger than expected biological differences b...
The nature and timing of the peopling of the Americas is a subject of intense debate. In particul... more The nature and timing of the peopling of the Americas is a subject of intense debate. In particular, it is unclear whether high levels of between-group craniometric diversity in South America result from multiple migrations or from local diversification processes. Previous attempts to explain this diversity have largely focused on testing alternative dispersal or gene flow models, reaching conflicting or inconclusive results. Here, a novel analytical framework is applied to three-dimensional geometric morphometric data to partition the effects of population divergence from geographically mediated gene flow to understand the ancestry of the early South Americans in the context of global human history. The results show that Paleoamericans share a last common ancestor with contemporary Native American groups outside, rather than inside, the Americas. Therefore, and in accordance with some recent genomic studies, craniometric data suggest that the New World was populated by multiple wav...
The nature and timing of the peopling of the Americas is a subject of intense debate. In particul... more The nature and timing of the peopling of the Americas is a subject of intense debate. In particular, it is unclear whether high levels of between-group craniometric diversity in South America result from multiple migrations or from local diversification processes. Previous attempts to explain this diversity have largely focused on testing alternative dispersal or gene flow models, reaching conflicting or inconclusive results. Here, a novel analytical framework is applied to three-dimensional geometric morphometric data to partition the effects of population divergence from geographically mediated gene flow to understand the ancestry of the earlySouth Americans in the context of global human history. The results show that Paleoamericans share a last common ancestor with contemporary Native American groups outside, rather than inside, the Americas.Therefore, and in accordance with some recent genomic studies, craniometric data suggest that the NewWorld was populated by multiple waves ...
American journal of physical anthropology, Oct 30, 2016
Estimation of the variance-covariance (V/CV) structure of fragmentary bioarchaeological populatio... more Estimation of the variance-covariance (V/CV) structure of fragmentary bioarchaeological populations requires the use of proxy extant V/CV parameters. However, it is currently unclear whether extant human populations exhibit equivalent V/CV structures. Random skewers (RS) and hierarchical analyses of common principal components (CPC) were applied to a modern human cranial dataset. Cranial V/CV similarity was assessed globally for samples of individual populations (jackknifed method) and for pairwise population sample contrasts. The results were examined in light of potential explanatory factors for covariance difference, such as geographic region, among-group distance, and sample size. S analyses showed that population samples exhibited highly correlated multivariate responses to selection, and that differences in RS results were primarily a consequence of differences in sample size. The CPC method yielded mixed results, depending upon the statistical criterion used to evaluate the h...
Human culture, biology, and health were shaped dramatically by the onset of agriculture ~12,000 y... more Human culture, biology, and health were shaped dramatically by the onset of agriculture ~12,000 years before present (BP). Subsistence shifts from hunting and gathering to agriculture are hypothesized to have resulted in increased individual fitness and population growth as evidenced by archaeological and population genomic data alongside a simultaneous decline in physiological health as inferred from paleopathological analyses and stature reconstructions of skeletal remains. A key component of the health decline inference is that relatively shorter statures observed for early farmers may (at least partly) reflect higher childhood disease burdens and poorer nutrition. However, while such stresses can indeed result in growth stunting, height is also highly heritable, and substantial inter-individual variation in the height genetic component within a population is typical. Moreover, extensive migration and gene flow were characteristics of multiple agricultural transitions worldwide. ...
OBJECTIVES Magnitudes of morphological integration may constrain or facilitate craniofacial shape... more OBJECTIVES Magnitudes of morphological integration may constrain or facilitate craniofacial shape variation. The aim of this study was to analyze how the magnitude of integration in the skull of Macaca fascicularis changes throughout ontogeny in relation to developmental and/or functional modules. MATERIALS AND METHODS Geometric morphometric methods were used to analyze the magnitude of integration in the macaque cranium and mandible in 80 juvenile and 40 adult M. fascicularis specimens. Integration scores in skull modules were calculated using integration coefficient of variation (ICV) of eigenvalues based on a resampling procedure. Resultant ICV scores between the skull as a whole, and developmental and/or functional modules were compared using Mann-Whitney U tests. RESULTS Results showed that most skull modules were more tightly integrated than the skull as a whole, with the exception of the chondrocranium in juveniles without canines, the chondrocranium/face complex and the mandibular corpus in adults, and the mandibular ramus in all juveniles. The chondrocranium/face and face/mandibular corpus complexes were more tightly integrated in juveniles than adults, possibly reflecting the influences of early brain growth/development, and the changing functional demands of infant suckling and later masticatory loading. This is also supported by the much higher integration of the mandibular ramus in adults compared with juveniles. DISCUSSION Magnitudes of integration in skull modules reflect developmental/functional mechanisms in M. fascicularis. However, the relationship between "evolutionary flexibility" and developmental/functional mechanisms was not direct or simple, likely because of the complex morphology, multifunctionality, and various ossification origins of the skull.
The human settlement of the Americas has been a topic of intense debate for centuries, and there ... more The human settlement of the Americas has been a topic of intense debate for centuries, and there is still no consensus on the tempo and mode of early human dispersion across the continent. When trying to explain the biological diversity of early groups across North, Central and South America, studies have defended a wide range of dispersion models that tend to oversimplify the diversity observed across the continent. In this study, we aim to contribute to this debate by exploring the cranial morphological affinities of four late Pleistocene/early Holocene specimens recovered from the caves of Quintana Roo, Mexico. The four specimens are among the earliest human remains known in the continent and permit the contextualization of biological diversity present during the initial millennia of human presence in the Americas. The specimens were compared to worldwide reference series through geometric morphometric analyses of 3D anatomical landmarks. Morphological data were analyzed through ...
Objectives: This study analyzes craniofacial shape variation in the Hehuang region of Northwest C... more 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 F ST 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. K E Y W O R D S 3D geometric morphometrics, Hehuang region, population history, skull morphology
Hominoid cranial evolution is characterized by substantial phenotypic diversity, yet the cause of... more Hominoid cranial evolution is characterized by substantial phenotypic diversity, yet the cause of this variability has rarely been explored. Quantitative genetic techniques for investigating evolutionary processes underlying morphological divergence are dependent on the availability of good ancestral models, a problem in hominoids where the fossil record is fragmentary and poorly understood. Here, we use a maximum likelihood approach based on a Brownian motion model of evolutionary change to estimate nested hypothetical ancestral forms from 15 extant hominoid taxa. These ancestors were then used to calculate rates of evolution along each branch of a phylogenetic tree using Lande's generalized genetic distance. Our results show that hominoid cranial evolution is characterized by strong stabilizing selection. Only two instances of directional selection were detected; the divergence of Homo from its last common ancestor with Pan, and the divergence of the lesser apes from their last common ancestor with the great apes. In these two cases, selection gradients reconstructed to identify the specific traits undergoing selection indicated that selection on basicranial flexion, cranial vault expansion and facial retraction characterizes the divergence of Homo, whereas the divergence of the lesser apes was defined by selection on neurocranial size reduction. This article is protected by copyright. All rights reserved.
American journal of physical anthropology, Jan 27, 2017
Debate persists regarding the biological makeup of European Ottoman communities settled during th... more Debate persists regarding the biological makeup of European Ottoman communities settled during the expansion of the Ottoman Empire during the 16th and 17th centuries, and the roles of conversion and migration in shaping demography and population history. The aim of this study was to perform an assessment of the biological affinities of three European Ottoman series based on craniometric data. Craniometric data collected from three Ottoman series from Hungary and Romania were compared to European and Anatolian comparative series, selected to represent biological affinity representative of historically recorded migration and conversion influences. Sex-separated samples were analyzed using D(2) -matrices, along with principal coordinates and PERMANOVA analyses to investigate biological affinities. Discriminant function analysis was employed to assign Ottoman individuals to two potential classes: European or Anatolian. Affinity analyses show larger than expected biological differences b...
The nature and timing of the peopling of the Americas is a subject of intense debate. In particul... more The nature and timing of the peopling of the Americas is a subject of intense debate. In particular, it is unclear whether high levels of between-group craniometric diversity in South America result from multiple migrations or from local diversification processes. Previous attempts to explain this diversity have largely focused on testing alternative dispersal or gene flow models, reaching conflicting or inconclusive results. Here, a novel analytical framework is applied to three-dimensional geometric morphometric data to partition the effects of population divergence from geographically mediated gene flow to understand the ancestry of the early South Americans in the context of global human history. The results show that Paleoamericans share a last common ancestor with contemporary Native American groups outside, rather than inside, the Americas. Therefore, and in accordance with some recent genomic studies, craniometric data suggest that the New World was populated by multiple wav...
The nature and timing of the peopling of the Americas is a subject of intense debate. In particul... more The nature and timing of the peopling of the Americas is a subject of intense debate. In particular, it is unclear whether high levels of between-group craniometric diversity in South America result from multiple migrations or from local diversification processes. Previous attempts to explain this diversity have largely focused on testing alternative dispersal or gene flow models, reaching conflicting or inconclusive results. Here, a novel analytical framework is applied to three-dimensional geometric morphometric data to partition the effects of population divergence from geographically mediated gene flow to understand the ancestry of the earlySouth Americans in the context of global human history. The results show that Paleoamericans share a last common ancestor with contemporary Native American groups outside, rather than inside, the Americas.Therefore, and in accordance with some recent genomic studies, craniometric data suggest that the NewWorld was populated by multiple waves ...
American journal of physical anthropology, Oct 30, 2016
Estimation of the variance-covariance (V/CV) structure of fragmentary bioarchaeological populatio... more Estimation of the variance-covariance (V/CV) structure of fragmentary bioarchaeological populations requires the use of proxy extant V/CV parameters. However, it is currently unclear whether extant human populations exhibit equivalent V/CV structures. Random skewers (RS) and hierarchical analyses of common principal components (CPC) were applied to a modern human cranial dataset. Cranial V/CV similarity was assessed globally for samples of individual populations (jackknifed method) and for pairwise population sample contrasts. The results were examined in light of potential explanatory factors for covariance difference, such as geographic region, among-group distance, and sample size. S analyses showed that population samples exhibited highly correlated multivariate responses to selection, and that differences in RS results were primarily a consequence of differences in sample size. The CPC method yielded mixed results, depending upon the statistical criterion used to evaluate the h...
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