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Adaptation, Dispersals and Phenotype: understanding the roles of climate,
natural selection and energetics in shaping global hunter-gatherer adaptability

Periodic Report Summary 2 - ADAPT (Adaptation, Dispersals and Phenotype: understanding the roles of climate, natural selection and energetics in shaping global hunter-gatherer adaptability.)

Our species, paradoxically, has both high levels of observable variation and low levels genetic diversity. Understanding the mechanisms which drive this variation remains one of the significant challenges in Anthropology.

The research of the ADaPt project investigates bioarchaeological evidence of human skeletal variation following the radiation and dispersal of our species to model the biological diversification of our species. We combine this work with the study of the energetic and adaptive consequences of variation among living humans among ultra-endurance athletes competing under different environmental conditions. The research integrates four projects designed to investigate components of this variation:

1. The analysis of Pleistocene and Holocene human skeletal variation relative to climatic models and neutral genetic distance, to identify environmental and random influences on human variation
2. The comparison of human and non-human primate skeletal adaptability associated with the colonisation of different environments throughout the Japanese archipelago, to differentiate cultural and biological mechanisms of human adaptability
3. The study of physiological trade-offs that occur during extreme energy stress, among ultra endurance athletes, to better understand how the body allocates energy to different resources necessary to survival in different environments.
4. The investigation of the relationship between performance among ultra-endurance athletes and skeletal variation, to better integrate human physiology with bioarchaeology and enhance our understanding of human adaptation in the past.

The first half of the project has been devoted to data collection, and we have successfully built a dataset of human skeletal variation that is globally representative, reflecting early hunter-gatherer occupations of most of the world’s major environmental regions. Within this initiative we have particularly emphasized the study of variation in the Japanese Archipelago, the only location where human foragers overlap with a non-human primate across a wide range of latitudes. In order to better analyse and interpret the patterns of human variation across these environments, we have generated high-resolution global climate maps, which we use to simulate environmental productivity and vegetation from 120,000 years ago to the present. In the second half of the project, we will analyse global patterns of human variation in time and space to these detailed environmental models, to interpret the influence of past environments on human diversity. Initial tests of our models demonstrate that migration history is the primary factor driving diversity among the Bantu and Tupi language families.

The project has competed fieldwork on energetic and life history trade-offs among ultra endurance athletes. As we progress with the analysis of the physiological changes of athlete participants during extreme energy deprivation, we have generated the first results of the study of phenotypic variation. Our results, thus far, provide the first means of comparing the norm of reaction of bone to activity among men and women, and demonstrate that, when compared to contemporary athletes, women show very high levels of mobility and labour intensity in the past. The results of this work are beginning to reframe our interpretations of human variation and activity in the past.