Arkadiusz Sołtysiak and Marta Bialon from the University of Warsaw recorded and analyzed fifty-nine dental non-metric traits in 350 human skeletons. The skeletons were retrieved from three sites (Tell Ashtara, Tell Masaikh, and Jebel Mashtale) in the lower Euphrates dating from the Early Bronze Age up to the Early Islamic period (Umayyad and Abbasid) and modern period. The results suggested that no major gene flow occurred in the middle Euphrates valley between the 3rd millennium BCE and the early 2nd millennium CE. However, the Mongolian invasion and the subsequent large depopulation in the northern parts of Mesopotamia in the 13th c. CE did instigate genetic heterogeneity. Another major population change occurred in the 17th c. CE after Bedouin tribes from the Arabian Peninsula took over large parts of Mesopotamia.