Aboriginal Root Reconsidered: A P-Rooted Topology for the Human Y-Chromosome Phylogeny

Abstract

Core Thesis The paper proposes an alternative topological framework—the P-Rooted Model—which treats haplogroup P (P0) as the aboriginal/founding root of the human Y-chromosome phylogenetic tree, anchored geographically in the Chittagong region (Karnaphuli river basin/Chandgaon, termed the Changaiye population) in southeastern Bangladesh. This model directly contrasts with the standard consensus tree (ISOGG/YFull), which roots the tree at African haplogroup A00 and treats P as a downstream, derived branch. Key Frameworks & Methodology Geographic-Reach Heuristic & Index: Rather than relying on sequence-based coalescent dating, the author uses a geography-first heuristic. Broad oceanic, circumpolar, or continental-terminal distributions are interpreted as markers of derivation (lateness) rather than antiquity. The heuristic is operationalized via a Geographic-Reach Index: Reach Score = (Macro-regions occupied) + (2 if oceanic/insular/circumpolar terminus, else 0) Higher scores indicate more derived, outward-radiating generations. Node-by-Node Topology: Root (Tier 0): P0 (Aboriginal Changaiye; Chittagong/Karnaphuli basin). Tier 1 (Direct Branches): Q (Aboriginal American), R (Aboriginal White), O (Asian), and D (Black 1st gen., proposed Tibet origin). Tier 2 (Secondary Nested Branches): C (via Q); I, N, J, H, L (via R); E (via D). Tier 3 (Terminal Leaves): J1, J2 (via J); A / B (paired terminal leaves via E, representing African haplogroups as the most derived generation). Companion Geogenetic Integration: The global topology extends the river-mediated dispersal mechanisms introduced in the companion paper applying fluvial corridor logic on a continental and global scale. (Maassoom, Y. A. (2026). Hydro-Genetic Dynamics: Fluvial Corridors as Selective Sorting Vectors and Channels for Geogenetic Evolution in the Bengal Basin and Himalayan Foothills. SSRN. https://ssrn.com/abstract=7352600)