Continuous mitochondrial diversity of Danube sturgeon species over millennia: insights from ancient DNA
Sturgeons, an iconic group of large fish inhabiting marine and freshwater ecosystems, have historically had significant economic and cultural value, particularly for their meat and eggs (caviar). Furthermore, sturgeons play a vital ecological role as mesopredators, regulating smaller prey species. In the Danube basin, the European (Acipenser sturio) and ship sturgeon (A. nudiventris) have become locally extinct, while populations of beluga (Huso huso), Russian (A. gueldenstaedtii), stellate (A. stellatus), and sterlet (A. ruthenus) have declined significantly since the 19th century due to overfishing, habitat loss, and pollution. Archaeological evidence suggests that sturgeon exploitation along the Danube began as early as 11.6 thousand years before present (kyr BP). This study explores the genetic landscape of Danube sturgeons over the past ~10 thousand years using ancient DNA extracted from archaeological specimens. Despite challenges posed by limited sample sizes and fragmented bones, our findings reveal continuous high genetic diversity among beluga, Russian, and ship sturgeon populations. In addition, modern beluga and Russian sturgeon in the Black Sea share identical mitochondrial haplotypes with species from historical periods. This data represents the first high-coverage sequencing of ancient sturgeon mitogenomes, enabling comprehensive analyses of their maternal lineage and establishing the foundation for further aDNA research.