Overview
J1-Y4331 is a downstream Arabian branch of the major J1-P58 expansion, originating among late Neolithic and early Bronze Age pastoral communities inhabiting northern Arabia, the southern Levant and the Hejaz corridor. These early groups operated within ecological zones defined by desert-steppe mobility, seasonal water access and the utilization of wells, wadis and oasis systems. Archaeological contexts relevant to this lineage include early desert encampments, pre-urban settlements along caravan routes and fortified oases that supported trade between Arabia and the Levant. During the Bronze and Iron Ages, populations bearing Y4331 participated in the demographic and tribal transformations that shaped the Syro-Arabian desert frontier. Downstream phylogenetic differentiation reveals clear founder effects corresponding to tribal confederations and sub-tribal expansions associated with the northern Hejaz and southern Jordan regions. These expansions continued into the early Islamic period, where further downstream diversification is evident.