Showing papers by "Stephen Shennan published in 2022"
TL;DR: In this article , the authors provided detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites and proposed that lactase nonpersistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe.
Abstract: In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years1. Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions2,3. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank4,5 cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.
33 citations
TL;DR: In this paper , the authors presented the largest existing repository of uncalibrated radiocarbon dates for the whole Near East from the Late Pleistocene to the Late Holocene (15,000 − 1,500 cal. yr. BP).
Abstract: To our knowledge, the dataset described in this paper represents the largest existing repository of uncalibrated radiocarbon dates for the whole Near East from the Late Pleistocene to the Late Holocene (15,000 – 1,500 cal. yr. BP). It is composed of 11,027 radiocarbon dates from 1,023 sites that have been collected comprehensively by cross-checking multiple sources (extant digital archives and databases, edited volumes, monographs, journals papers, archaeological excavation reports, etc.) under the umbrella of the Leverhulme Trust funded project “Changing the Face of the Mediterranean” and of the ERC project “CLASS – Climate, Landscape, Settlement and Society: Exploring Human-Environment Interaction in the Ancient Near East”. This is an ongoing dataset that will be updated step by step with newly published radiocarbon dates.
4 citations
2 citations
TL;DR: In this article , a non-equilibrium neutral model is proposed to analyse the cultural system under consideration at any point in time, which gives an indication whether observed changes in the frequency distributions of a set of cultural variants between two time points are consistent with the random copying hypothesis.
Abstract: . Neutral evolution is a frequently used model to analyse changes in frequencies of cultural variants over time. Variants are chosen to be copied according to their relative frequency and new variants are introduced by a process of random mutation. Here we present a non-equilibrium neutral model which accounts for temporally varying population sizes and mutation rates and makes it possible to analyse the cultural system under consideration at any point in time. This framework gives an indication whether observed changes in the frequency distributions of a set of cultural variants between two time points are consistent with the random copying hypothesis. We find that the likelihood of the existence of the observed assemblage at the end of the considered time period (expressed by the probability of the observed number of cultural variants present in the population during the whole period under neutral evolution) is a powerful indicator of departures from neutrality. Further, we study the effects of frequency-dependent selection on the evolutionary trajectories and present a case study of change in the decoration of pottery in early Neolithic Central Europe. Based on the framework developed we show that neutral evolution is not an adequate description of the observed changes in frequency.