Overview
J1-ZS1120 is a downstream component of the J1-L147.1 Arabian expansion and originated among pastoralist populations inhabiting the northern Arabian steppe and adjacent Hejaz regions during the late Neolithic through early Bronze Age transition. These ancestral groups utilized desert mobility systems dependent on wells, wadis and rotational pasture access, forming the demographic substrate for later North Arabian tribalization. During the Bronze and Iron Ages, ZS1120-bearing communities took part in the formation of desert tribal networks extending across northern Arabia, Transjordan and western Mesopotamia. Its downstream phylogeny shows tight founder effects linked to Hejaz, Najd and Jordanian clan structures. Later demographic episodes during the early Islamic period extended certain subbranches into Iraq and the Gulf region.