Ancient plastid genomes solve the tree species mystery of the imperial wood “Nanmu” in the Forbidden City, the largest existing wooden palace complex in the world

Societal Impact Statement Combining natural and social science approaches to conduct archeological research on wooden cultural relics is important for exploring major aspects of ancient civilizations. The Forbidden City in Beijing, China, the largest existing palace complex world. We examined DNA imperial wood “Nanmu” specimens taken from representative structural components City, order provide a new perspective long-standing dispute about its species. This allowed us accurately identify properly restore these artifacts improved our understanding past interactions between plant distribution, forest resources, human activities. Summary Exploring life styles production methods generations using resources can help improve civilization. Nanmu, known high quality, was exclusively used construction 15th–19th centuries yet species has been subject debate. Here, we revisit this unresolved problem, morphology (aDNA) analyze 21 centuries-old Nanmu sampled palaces City. Cytochemical staining demonstrated that endogenous aDNA sporadically occurs ray parenchyma cells specimens. High-quality plastid genomes were retrieved woods first time via an capture method, with 90%–100% coverage (137,663–152,805 bp) sequence depths 27.05- 1409.94-fold. Utilizing genomes, results demonstrate Phoebe zhennan hui are most likely main finding diverges prevailing view encompasses whole genus even close relative Machilus. It also shows stringent criteria when selecting materials By combining morphological traits analyses, solution identifying timber architecture, increase way which recognized utilized by ancestors despite lack taxonomic framework times.