Long-term trends in human body size track regional variation in subsistence transitions and growth acceleration linked to dairying

Abstract

Evidence for a reduction in stature between Mesolithic foragers and Neolithic farmers has been interpreted as reflective of declines in health, however, our current understanding of this trend fails to account for the complexity of cultural and dietary transitions or the possible causes of phenotypic change. The agricultural transition was extended in primary centers of domestication and abrupt in regions characterized by demic diffusion. In regions such as Northern Europe where foreign domesticates were difficult to establish, there is strong evidence for natural selection for lactase persistence in relation to dairying. We employ broad-scale analyses of diachronic variation in stature and body mass in the Levant, Europe, the Nile Valley, South Asia, and China, to test three hypotheses about the timing of subsistence shifts and human body size, that: 1) the adoption of agriculture led to a decrease in stature, 2) there were different trajectories in regions of in situ domestication or cultural diffusion of agriculture; and 3) increases in stature and body mass are observed in regions with evidence for selection for lactase persistence. Our results demonstrate that 1) decreases in stature preceded the origins of agriculture in some regions; 2) the Levant and China, regions of in situ domestication of species and an extended period of mixed foraging and agricultural subsistence, had stable stature and body mass over time; and 3) stature and body mass increases in Central and Northern Europe coincide with the timing of selective sweeps for lactase persistence, providing support for the "Lactase Growth Hypothesis."

Keywords: agriculture; bioarchaeology; domestication; health; human adaptation.

Fig. 1.

Scatterplots with Lowess lines illustrating broad patterns of (A) stature variation, illustrating a general decline over 30 kya, followed by stability through the terminal Pleistocene and early Holocene, in the period characterized by the origin and diffusion of agriculture in most regions; (B) body mass which declines until the period of the broad adoption of agriculture following 7 kya. Shaded regions represent 95% confidence intervals around fit lines.

Fig. 2.

Scatterplots with Lowess lines illustrating long-term trends in (A) stature and (B) body mass in the Levant, a region representing the earliest transition to agriculture and the in situ domestication of numerous plant and animal species. Shaded regions represent 95% confidence intervals around fit lines.

Fig. 3.

Scatterplots with LOWESS lines illustrating temporal variation in stature in Southern, Central, and Northern Europe, the Nile Valley, South Asia, and China. Lowess smoothing parameter = 0.8 except as follows: Northern Europe = 0.9, Nile = 1.1, South Asia = 1.0. Shaded regions represent 95% confidence intervals around fit lines.

Fig. 4.

Scatterplots with LOWESS lines illustrating temporal variation in body mass in Southern, Central and Northern Europe, the Nile Valley, South Asia, and China. Lowess smoothing parameter: Southern Europe = 0.9, Central Europe = 0.8, Northern Europe = 0.9, Nile Valley = 1.1, South Asia = 1.1, China = 1.0. Shaded regions represent 95% confidence intervals around fit lines.

Fig. 5.

Long-term trends in stature (above) and body mass (below) in subregions of Northern Europe. Lowess smoothing parameters for stature: Britain = 1.0, Scandinavia = 1.0, Baltics = 1.0. Lowess smoothing parameters for body mass: Britain = 0.9, South Scandinavia = 1.0, Baltics = 1.0. Shaded regions represent 95% confidence intervals around fit lines.

Fig. 6.

Heatmaps of spatiotemporal variation in stature and body mass throughout Holocene Europe. Red points denote site locations.