Overview
J1-ZS2128 is a downstream component of the Arabian-rooted J1-L147.1 radiation and formed among pastoral populations occupying northern Arabia during the early Bronze Age. These groups followed grazing circuits centered on desert wells, scattered oasis systems and wadis that provided seasonal access to water. Their demographic structure corresponds to early tribal formations that later shaped historic Hejazi and North Arabian societies. During the Bronze and Iron Ages, ZS2128-bearing groups expanded across the desert belt between the Hejaz, Najd and the western Mesopotamian frontier. Downstream structure reveals several founder-driven expansions associated with clan-based segmentation. With the rise of the early Islamic world, additional dispersal moved ZS2128 lineages into Iraq and the Gulf region, where further microbranches developed.