Interpopulation differences in the severity of early childhood stress in ancient Lower Nubia: Implications for hypotheses of X-group origins

The origins of the Lower Nubian X-Group population (a.d. 300-600) are presently controversial. Some argue for migration; others argue for biological and cultural evolution in situ. A recent paleoepidemiological study has some bearing on this problem. It shows the X-Group experiencing significantly less early childhood stress than the preceding Meroitic population (100 b.c.-a.d. 300). Such a difference could be taken as evidence for migration, but the direction of the difference suggests otherwise. Meroitic improvements in irrigation technology likely led to high prevalences of helminthic disease, with correspondingly high levels of early childhood stress. Similarly high levels of parasitemia and stress would have been expected in a newly migrant population. The actual decline in stress levels thus does not seem consistent with an hypothesis of population replacement. This finding lends additional support to the argument for biological and cultural continuity in ancient Lower Nubia.