It goes way back

Kevin Lewis

January 19, 2019

Health and Wealth in the Roman Empire
Willem Jongman, Jan Jacobs & Geertje Klein Goldewijk
Economics & Human Biology, forthcoming

Ancient Rome was the largest and most populous empire of its time, and the largest pre-industrial state in European history. Recent though not universally accepted research suggests that at least for the most populous central periods of its history standard of living was also rather higher than before or after. To trace whether this is also reflected in Roman biological standard of living, we present the first large and more or less comprehensive dataset, based on skeletal data for some 10,000 individuals, covering all periods of Roman history, and all regions (even if inevitably unequally). We discuss both the methodologies that we developed and the historical results. Instead of reconstructing heights from the long bones assuming fixed body proportions or from one individual long bone, we apply exploratory factor analysis and calculate factor scores for 50-year periods. Our measure of the biological standard of living declined during the last two centuries B.C. and started to improve again, slowly at first, from the second century A.D. It correlated negatively with population, but also with other aspects of standard of living such as wages or diets.

Precise timing of abrupt increase in dust activity in the Middle East coincident with 4.2 ka social change
Stacy Carolin et al.
Proceedings of the National Academy of Sciences, 2 January 2019, Pages 67-72

The extent to which climate change causes significant societal disruption remains controversial. An important example is the decline of the Akkadian Empire in northern Mesopotamia ∼4.2 ka, for which the existence of a coincident climate event is still uncertain. Here we present an Iranian stalagmite record spanning 5.2 ka to 3.7 ka, dated with 25 U/Th ages that provide an average age uncertainty of 31 y (1σ). We find two periods of increased Mg/Ca, beginning abruptly at 4.51 and 4.26 ka, and lasting 110 and 290 y, respectively. Each of these periods coincides with slower vertical stalagmite growth and a gradual increase in stable oxygen isotope ratios. The periods of high Mg/Ca are explained by periods of increased dust flux sourced from the Mesopotamia region, and the abrupt onset of this dustiness indicates threshold behavior in response to aridity. This interpretation is consistent with existing marine and terrestrial records from the broad region, which also suggest that the later, longer event beginning at 4.26 ka is of greater regional extent and/or amplitude. The chronological precision and high resolution of our record indicates that there is no significant difference, at decadal level, between the start date of the second, larger dust event and the timing of North Mesopotamia settlement abandonment, and furthermore reveals striking similarity between the total duration of the second dust event and settlement abandonment. The Iranian record demonstrates this region’s threshold behavior in dust production, and its ability to maintain this climate state for multiple centuries naturally.

Multiple episodes of interbreeding between Neanderthal and modern humans
Fernando Villanea & Joshua Schraiber
Nature Ecology & Evolution, January 2019, Pages 39–44

Neanderthals and anatomically modern humans overlapped geographically for a period of over 30,000 years following human migration out of Africa. During this period, Neanderthals and humans interbred, as evidenced by Neanderthal portions of the genome carried by non-African individuals today. A key observation is that the proportion of Neanderthal ancestry is ~12–20% higher in East Asian individuals relative to European individuals. Here, we explore various demographic models that could explain this observation. These include distinguishing between a single admixture event and multiple Neanderthal contributions to either population, and the hypothesis that reduced Neanderthal ancestry in modern Europeans resulted from more recent admixture with a ghost population that lacked a Neanderthal ancestry component (the ‘dilution’ hypothesis). To summarize the asymmetric pattern of Neanderthal allele frequencies, we compiled the joint fragment frequency spectrum of European and East Asian Neanderthal fragments and compared it with both analytical theory and data simulated under various models of admixture. Using maximum-likelihood and machine learning, we found that a simple model of a single admixture did not fit the empirical data, and instead favour a model of multiple episodes of gene flow into both European and East Asian populations. These findings indicate a longer-term, more complex interaction between humans and Neanderthals than was previously appreciated.

Close companions: Early evidence for dogs in northeast Jordan and the potential impact of new hunting methods
Lisa Yeomans, Louise Martin & Tobias Richter
Journal of Anthropological Archaeology, March 2019, Pages 161-173

Current evidence suggests domestications of the dog were incipient developments in many areas of the world. In southwest Asia this process took place in the Late Epipalaeolithic Natufian (∼14,500–11,600 cal BP) with the earliest evidence originating from the Mediterranean zone of the southern Levant. This paper presents new data for the importance of early domestic dogs to human groups in the region beyond this ‘core’ area where the Late Pleistocene and Early Holocene environment is usually thought of as less favourable for human occupation. By the Pre-Pottery Neolithic A it is demonstrated that dogs were living alongside humans in significant numbers. Most discussions of early domestic dogs assume that these animals would have facilitated the hunting of larger prey following the innate behavioural traits of their wolf ancestors. This paper suggests that the benefits of hunting with dogs could also extend to the capture of smaller prey. An increase in the hunting of such animals, as part of the broad-spectrum revolution, was not necessarily a response limited to resource reduction in the Late Pleistocene and factors such as new hunting methods need consideration.

Neandertal Introgression Sheds Light on Modern Human Endocranial Globularity
Philipp Gunz et al.
Current Biology, 7 January 2019, Pages 120-127

One of the features that distinguishes modern humans from our extinct relatives and ancestors is a globular shape of the braincase. As the endocranium closely mirrors the outer shape of the brain, these differences might reflect altered neural architecture. However, in the absence of fossil brain tissue, the underlying neuroanatomical changes as well as their genetic bases remain elusive. To better understand the biological foundations of modern human endocranial shape, we turn to our closest extinct relatives: the Neandertals. Interbreeding between modern humans and Neandertals has resulted in introgressed fragments of Neandertal DNA in the genomes of present-day non-Africans. Based on shape analyses of fossil skull endocasts, we derive a measure of endocranial globularity from structural MRI scans of thousands of modern humans and study the effects of introgressed fragments of Neandertal DNA on this phenotype. We find that Neandertal alleles on chromosomes 1 and 18 are associated with reduced endocranial globularity. These alleles influence expression of two nearby genes, UBR4 and PHLPP1, which are involved in neurogenesis and myelination, respectively. Our findings show how integration of fossil skull data with archaic genomics and neuroimaging can suggest developmental mechanisms that may contribute to the unique modern human endocranial shape.


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