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Buck LT, De Groote I, Hamada Y, Hassett BR, Ito T, Stock JT. Evidence of different climatic adaptation strategies in humans and non-human primates. Sci Rep 2019; 9:11025. [PMID: 31363121 PMCID: PMC6667491 DOI: 10.1038/s41598-019-47202-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 07/05/2019] [Indexed: 12/17/2022] Open
Abstract
To understand human evolution it is critical to clarify which adaptations enabled our colonisation of novel ecological niches. For any species climate is a fundamental source of environmental stress during range expansion. Mammalian climatic adaptations include changes in size and shape reflected in skeletal dimensions and humans fit general primate ecogeographic patterns. It remains unclear however, whether there are also comparable amounts of adaptation in humans, which has implications for understanding the relative importance of biological/behavioural mechanisms in human evolution. We compare cranial variation between prehistoric human populations from throughout Japan and ecologically comparable groups of macaques. We compare amounts of intraspecific variation and covariation between cranial shape and ecological variables. Given equal rates and sufficient time for adaptation for both groups, human conservation of non-human primate adaptation should result in comparable variation and patterns of covariation in both species. In fact, we find similar amounts of intraspecific variation in both species, but no covariation between shape and climate in humans, contrasting with strong covariation in macaques. The lack of covariation in humans may suggest a disconnect in climatic adaptation strategies from other primates. We suggest this is due to the importance of human behavioural adaptations, which act as a buffer from climatic stress and were likely key to our evolutionary success.
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Affiliation(s)
- L T Buck
- PAVE research group, Department of Archaeology, University of Cambridge, Pembroke Street, Cambridge, CB2 3QG, UK. .,Human Origins Research Group, Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK. .,Department of Anthropology, University of California Davis, 1 Shields Avenue, Davis, 95616, CA, USA.
| | - I De Groote
- School of Natural Science and Psychology, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Y Hamada
- Primate Research Institute, Kyoto University, Inuyama, Aichi, 484-8506, Japan
| | - B R Hassett
- Human Origins Research Group, Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.,Institute of Archaeology, University College London, 31-4 Gordon Square, London, WC1H 0PY, UK
| | - T Ito
- Primate Research Institute, Kyoto University, Inuyama, Aichi, 484-8506, Japan
| | - J T Stock
- PAVE research group, Department of Archaeology, University of Cambridge, Pembroke Street, Cambridge, CB2 3QG, UK.,Department of Anthropology, Western University, London, Ontario, N6A 3K7, Canada.,Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Strasse 10, D-07745, Jena, Germany
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Abstract
Environmental temperature can have a surprising impact on extremity growth in homeotherms, but the underlying mechanisms have remained elusive for over a century. Limbs of animals raised at warm ambient temperature are significantly and permanently longer than those of littermates housed at cooler temperature. These remarkably consistent lab results closely resemble the ecogeographical tenet described by Allen's "extremity size rule," that appendage length correlates with temperature and latitude. This phenotypic growth plasticity could have adaptive significance for thermal physiology. Shortened extremities help retain body heat in cold environments by decreasing surface area for potential heat loss. Homeotherms have evolved complex mechanisms to maintain tightly regulated internal temperatures in challenging environments, including "facultative extremity heterothermy" in which limb temperatures can parallel ambient. Environmental modulation of tissue temperature can have direct and immediate consequences on cell proliferation, metabolism, matrix production, and mineralization in cartilage. Temperature can also indirectly influence cartilage growth by modulating circulating levels and delivery routes of essential hormones and paracrine regulators. Using an integrated approach, this article synthesizes classic studies with new data that shed light on the basis and significance of this enigmatic growth phenomenon and its relevance for treating human bone elongation disorders. Discussion centers on the vasculature as a gateway to understanding the complex interconnection between direct (local) and indirect (systemic) mechanisms of temperature-enhanced bone lengthening. Recent advances in imaging modalities that enable the dynamic study of cartilage growth plates in vivo will be key to elucidating fundamental physiological mechanisms of long bone growth regulation.
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Affiliation(s)
- Maria A Serrat
- Department of Anatomy and Pathology, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia
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Abstract
Obesity is an escalating threat of pandemic proportions, currently affecting billions of people worldwide and exerting a devastating socioeconomic influence in industrialized countries. Despite intensive efforts to curtail obesity, results have proved disappointing. Although it is well recognized that obesity is a result of gene-environment interactions and that predisposition to obesity lies predominantly in our evolutionary past, there is much debate as to the precise nature of how our evolutionary past contributed to obesity. The "thrifty genotype" hypothesis suggests that obesity in industrialized countries is a throwback to our ancestors having undergone positive selection for genes that favored energy storage as a consequence of the cyclical episodes of famine and surplus after the advent of farming 10 000 years ago. Conversely, the "drifty genotype" hypothesis contends that the prevalence of thrifty genes is not a result of positive selection for energy-storage genes but attributable to genetic drift resulting from the removal of predative selection pressures. Both theories, however, assume that selection pressures the ancestors of modern humans living in western societies faced were the same. Moreover, neither theory adequately explains the impact of globalization and changing population demographics on the genetic basis for obesity in developed countries, despite clear evidence for ethnic variation in obesity susceptibility and related metabolic disorders. In this article, we propose that the modern obesity pandemic in industrialized countries is a result of the differential exposure of the ancestors of modern humans to environmental factors that began when modern humans left Africa around 70 000 years ago and migrated through the globe, reaching the Americas around 20 000 years ago. This article serves to elucidate how an understanding of ethnic differences in genetic susceptibility to obesity and the metabolic syndrome, in the context of historic human population redistribution, could be used in the treatment of obesity in industrialized countries.
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Affiliation(s)
- Dyan Sellayah
- MRC Harwell (D.S., R.D.C.), Genetics of Type 2 Diabetes, Harwell Science and Innovation Campus, Harwell OX11 ORD, United Kingdom; Department of Physiology, Anatomy and Genetics (D.S.), University of Oxford, Oxford OX1 3PT, United Kingdom; and Institute of Developmental Sciences (F.R.C.), University of Southampton, Southampton SO16 6YD, United Kingdom
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Evteev A, Cardini AL, Morozova I, O'Higgins P. Extreme climate, rather than population history, explains mid-facial morphology of northern asians. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 153:449-62. [DOI: 10.1002/ajpa.22444] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 11/21/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Andrej Evteev
- Anuchin Research Institute and Museum of Anthropology, Lomonosov Moscow State University; Moscow 125009 Russia
| | - Andrea L. Cardini
- Dipartimento di Scienze Chimiche e Geologiche; Università di Modena e Reggio Emilia; 41121 Modena Italy
- Centre for Anatomical and Human Sciences; Hull York Medical School, University of York; Heslington York YO10 5DD UK
- Centre for Forensic Science; University of Western Australia; Crawley, Perth Western Australia 6009 Australia
| | - Irina Morozova
- Human Genetics Laboratory; Vavilov Institute of General Genetics Russian Academy of Sciences; Moscow 119991 Russia
| | - Paul O'Higgins
- Centre for Anatomical and Human Sciences; Hull York Medical School, University of York; Heslington York YO10 5DD UK
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Rae TC, Vidarsdóttir US, Jeffery N, Steegmann AT. Developmental response to cold stress in cranial morphology of Rattus: implications for the interpretation of climatic adaptation in fossil hominins. Proc Biol Sci 2006; 273:2605-10. [PMID: 17002945 PMCID: PMC1635465 DOI: 10.1098/rspb.2006.3629] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adaptation to climate occupies a central position in biological anthropology. The demonstrable relationship between temperature and morphology in extant primates (including humans) forms the basis of the interpretation of the Pleistocene hominin Homo neanderthalensis as a cold-adapted species. There are contradictory signals, however, in the pattern of primate craniofacial changes associated with climatic conditions. To determine the direction and extent of craniofacial change associated with temperature, and to understand the proximate mechanisms underlying cold adaptations in vertebrates in general, dry crania from previous experiments on cold- and warm-reared rats were investigated using computed tomography scanning and three-dimensional digitization of cranial landmarks. Aspects of internal and external cranial morphology were compared using standard statistical and geometric morphometric techniques. The results suggest that the developmental response to cold stress produces subtle but significant changes in facial shape, and a relative decrease in the volume of the maxillary sinuses (and nasal cavity), both of which are independent of the size of the skull or postcranium. These changes are consistent with comparative studies of temperate climate primates, but contradict previous interpretations of cranial morphology of Pleistocene Hominini.
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Affiliation(s)
- Todd C Rae
- Evolutionary Anthropology Research Group, Department of Anthropology, University of Durham, 43 Old Elvet, Durham DH1 3HN, UK.
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Steegmann AT, Cerny FJ, Holliday TW. Neandertal cold adaptation: physiological and energetic factors. Am J Hum Biol 2002; 14:566-83. [PMID: 12203812 DOI: 10.1002/ajhb.10070] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
European Neandertals employed a complex set of physiological cold defenses, homologous to those seen in contemporary humans and nonhuman primates. While Neandertal morphological patterns, such as foreshortened extremities and low relative surface-area, may have explained some of the variance in cold resistance, it is suggested the adaptive package was strongly dependent on a rich array of physiological defenses. A summary of the environmental cold conditions in which the Neandertals lived is presented, and a comparative ethnographic model from Tierra del Fuego is used. Muscle and subcutaneous fat are excellent "passive" insulators. Neandertals were quite muscular, but it is unlikely that they could maintain enough superficial body fat to offer much cold protection. A major, high-energy metabolic adaptation facilitated by modest amounts of highly thermogenic brown adipose tissue (BAT) is proposed. In addition, Neandertals would have been protected by general mammalian cold defenses based on systemic vasoconstriction and intensified by acclimatization, aerobic fitness, and localized cold--induced vasodilation. However, these defenses are energetically expensive. Based on contemporary data from circumpolar peoples, it is estimated that Neandertals required 3,360 to 4,480 kcal per day to support strenuous winter foraging and cold resistance costs. Several specific genetic cold adaptations are also proposed--heat shock protein (actually, stress shock protein), an ACP*1 locus somatic growth factor, and a specialized calcium metabolism not as yet understood.
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Affiliation(s)
- A Theodore Steegmann
- Department of Anthropology, 380 MFAC, SUNY Buffalo, Buffalo, New York 14261, USA.
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Siegel MI, Doyle WJ, Kelley C. Heat stress, fluctuating asymmetry and prenatal selection in the laboratory rat. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1977; 46:121-6. [PMID: 556888 DOI: 10.1002/ajpa.1330460115] [Citation(s) in RCA: 87] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent studies have demonstrated that stress may increase the fluctuating asymmetry of teeth and limbs in laboratory animals. The present study investigates the effects of heat on such parameters. Pregnant laboratory rats are exposed to temperatures of 33 degrees C during gestation. Increases in fluctuating asymmetry of dental dimensions as well as bone density are found for the pups of such females when compared to unstressed controls. A general increase in limb lengths is also reported for young of heat stressed animals. Prenatal selection with differential survival is suggested as a possible explanation for differences found between the experimental and control animals.
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Riesenfeld A. Compact bone changes in cold-exposed rats. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1976; 44:111-2. [PMID: 1247105 DOI: 10.1002/ajpa.1330440115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Rats exposed to cold stress show a reduction of relative cortical thickness in their long bones. The reaction resembles reduction of cortical thickness observed in Asiatic humans of the Mongoloid race, in whom many morphological features have been postulated to be cold-adaptive. However, until it can be established that the physiological processes underlying the experimental and phylogenetic condition are similar, no extrapolation can be attempted from the one to the other.
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