Project description:Hainan Island harbours an extraordinary diversity of Gesneriaceae with 14 genera and 23 species, amongst which two species and one variety are recognised in the genus Oreocharis. These three Oreocharis taxa are all Hainan-endemics and show a complex geographical distribution pattern with considerable morphological intermixtures. In this study, we combined DNA (nuclear ITS sequences and cpDNAtrnL-trnF and ycf1b) to evaluate genetic delimitation for 12 Oreocharis populations from the island, together with morphological similarity analysis using 16 morphological traits. The results showed Hainan Oreocharis taxa were monophyletic with relative low genetic diversity within populations, highly significant genetic differentiation amongst populations and a significant phylogeographical structure. The 12 populations formed three genetically distinct groups, roughly correspondent to the currently recognised two species and one unknown lineage. The PCA analyses of morphological traits indicate three distinctive groups, differing mainly in petal colour and corolla shapes. The roles of river and mountain isolations in the origin and distribution of these three lineages are discussed.
Project description:Background: Ependymomas encompass multiple, clinically relevant tumor types based on localization and molecular profiles. Although tumors of the methylation class “spinal ependymoma” (SP-EPN) represent the most common intramedullary neoplasms in children and adults, their developmental origin is ill-defined, molecular data are scarce, and the potential heterogeneity within SP-EPN remains unexplored. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations, but neither types and frequency of these alterations nor their clinical meaning have been described in a large, epigenetically defined series. Methods: We mapped SP-EPN transcriptomes (n=76) to developmental atlases of the developing and adult spinal cord to uncover potential developmental origins of these tumors. In addition, transcriptomic, epigenetic (n=234), genetic (n=140), and clinical analyses (n=115) were integrated for a detailed overview on this entity. Results: Integration of transcriptomic ependymoma data with single-cell atlases of the spinal cord identified mature adult ependymal cells to display highest similarities to SP-EPN. Unsupervised hierarchical clustering of tumor data together with integrated analysis of methylation profiles identified two molecular SP-EPN subtypes. Subtype 1 predominantly contained NF2 wild type sequences with regular NF2 expression but revealed more extensive copy number alterations. Subtype 2 harbored previously known germline or sporadic NF2 mutations and was NF2-deficient in most cases, more often showed multilocular disease, and demonstrated a significantly reduced progression-free survival. Conclusion: Based on integrated molecular profiling of a large tumor series we identify two distinct SP-EPN subtypes with important implications for genetic counseling, patient surveillance, and drug development priorities.