Overview
G2a2b1a54 is a downstream branch of the prolific Anatolian-centered G-M406 expansion, representing a demographic lineage that ties the southwestern Black Sea littoral with the inner Thracian–Anatolian contact zone. Its tmrca suggests that the branch diversified during the classical, Roman and early medieval periods, when Thrace and the Marmara hinterland acted as a major frontier between Anatolia, the Balkans and the Black Sea networks. The lineage’s deep ancestry stems from inland Anatolian M406 sources, but its later shaping appears tied to communities situated between the Marmara lowlands and the western Pontic steppes.
Its demographic profile—moderate internal branching, several regionally anchored subclusters, and lack of explosive founder radiation—matches populations living in rural highland/lowland transitional landscapes that experienced continuous but modest population turnover across the Byzantine period.
Geographic distribution
Modern distributions place G2a2b1a54 across the Marmara basin (Bursa, Bilecik, Sakarya, Kocaeli), western Black Sea (Zonguldak, Kastamonu, Bartın), and parts of European Turkey (Thrace). The lineage also appears in Bulgaria and Romania at low frequencies, consistent with movements during late antiquity and the early medieval Danubian frontier era.
Low-level instances in Greece and Moldova likely reflect secondary mobility rather than primary geographic roots.
Ancient DNA
- Late Roman/Byzantine individuals from the Marmara hinterland display M406 signatures compatible with the FT1259xx cluster.
- Archaeogenetic models for Thrace and the western Black Sea regularly incorporate Anatolian-derived paternal inputs matching G2a2b1a54’s profile.
- Black Sea coastal classical-era samples contain G2a2b1a-like Y patterns aligned with regions where FT1259xx derivatives persist today.
Phylogeny & subclades
G2a2b1a54 is defined by FT125904 and a suite of FT1259xx SNPs forming a compact internal cluster within the M406 megabranch. Substructure indicates at least two mid-level subbranches representing the Marmara interior and the western Black Sea highlands. The lineage fits the model of regionally persistent Anatolian-derived groups who were incorporated into Thracian, Roman and Byzantine provincial structures.
- G2a2b1a54* (basal Marmara–Pontic form)
- G2a2b1a54a (FT125931-linked Marmara cluster)
- G2a2b1a54b (western Black Sea microbranch)
Notes & context
G2a2b1a54 clarifies the demographic role of Anatolian-derived paternal lines within the Marmara–Thrace–western Black Sea crossroads, a key region in late antiquity and early medieval population history. Its addition completes an important segment of the M406 map.
References & external links