Genetic structure and conservation implications of Lancea tibetica (Mazaceae), a traditional Tibetan medicinal plant endemic to the Qinghai- Tibet Plateau.

Background: Allopatric divergence is often initiated by geological uplift and climate oscillations. Qinghai-Tibet Plateau is an excellent place for such research because the plants of this area have experienced such historical processes as glacial contraction, interglacial expansion and geographical isolation. Here in this study, we used Genotyping-By-Sequencing data to investigate allopatric divergence of Lancea tibetica, an endemic herb to the Qinghai-Tibet Plateau. A total of 12,005 high-quality single nucleotide polymorphisms were obtained from 183 individuals of 23 natural distribution areas.

Results: Our results confirm that L. tibetica is divided into Northern and Southern groups, separated by the Tangula Mountains, Nyainqentanglha Mountains, and the Salween River. Demographic modeling indicated a bottleneck event around 300 kya, followed by gene flow and a recent expansion in both groups. Geographic isolation and climatic variation are likely the primary factors shaping the population structure of this species. Species distribution models reveal that elevation is the most significant factor influencing the distribution of L. tibetica, followed by precipitation and temperature. In scenarios of future global warming, suitable habitats for L. tibetica are likely to be significantly reduced, with an anticipated migration to higher altitudes. Given the current and projected distribution patterns of L. tibetica, the implementation of in-situ conservation and commercial cultivation measures is particularly urgent.

Conclusions: Our study contributes insights into understanding the genetic variation and distribution pattern of species in the Qinghai-Tibet Plateau and its adjacent areas, serving as a valuable reference for future conservation efforts.