No abstract

To evaluate the role of Quaternary refugial isolation in allopatric (incipient) speciation of East Asian temperate forest biotas, we analyzed amplified fragment length polymorphisms (AFLPs) and the breeding system in Dysosma versipellis. The study revealed that D. versipellis is mostly self-incompatible, genetically highly subdivided and depauperate at the population level (e.g., Φ(ST) = 0.572/H(E) = 0.083), and characterized by a low pollen-to-seed migration ratio (r ≈ 4.0). The latter outcome likely reflects limited pollen flow in a low-seed disperser whose hypothesized "sapromyophilous" flowers undergo scarce, inefficient, and likely specialized cross-pollination by small Anoplodera beetles, rather than carrion flies as assumed previously. In consequence, fruit set in D. versipellis was strongly pollen-limited. Our AFLP data support the hypothesis of a long-standing cessation of gene flow between western and central eastern populations, consistent with previous chloroplast DNA data. This phylogeographic pattern supports the role of the Sichuan Basin as a floristic boundary separating the Sino-Himalayan vs. Sino-Japanese Forest subkingdoms. Our genetic data of D. versipellis also imply that temperate deciduous forest elements to the west and the east of this basin responded differently to Quaternary climate change, which may have triggered or is leading to allopatric (incipient) speciation.

Species of Podophyllum, Dysosma, Sinopodophyllum, and Diphylleia, genera from Podophylloideae of Berberidaceae, have long been used in traditional herbal medicine in East Asia and/or North America. Accurate identification of the species of these four genera is crucial to their medicinal uses. In this study, we tested the utility of nine barcodes (matK, rbcL, atpH-atpI, rpl32-trnL UAG , rps18-clpp, trnL-trnF, trnL-ndhJ, trnS-trnfM, and internal transcribed spacer (ITS)) to discriminate different species of Podophylloideae. Thirty-six individuals representing 12 species of Podophylloideae were collected from different locations in China, Japan, and North America. We assessed the feasibility of amplification and sequencing of all markers, examined the levels of the barcoding gap based on DNA sequence divergence between ranges of intra-and interspecific variation using pairwise distances, and further evaluated successful identifications using each barcode by similarity-based and tree-based methods. Results showed that nine barcodes, except rps18-clpp, have a high level of primer universality and sequencing success. As a single barcode, ITS has the most variable sites, greater intra-and interspecific divergences, and the highest species discrimination rate (83%), followed by matK which has moderate variation and also high species discrimination rates. However, these species can also be discriminated by ITS alone, except Dysosma versipellis (Hance) M. Cheng ex T. S. Ying and D. pleiantha (Hance) Woodson. The combination of ITS þ matK did not improve species resolution over ITS alone. Thus, we propose that ITS may be used as a sole region for identification of most species in Podophylloideae. The failure of ITS to distinguish D. versipellis and D. pleiantha is likely attributed to incomplete lineage sorting due to recent divergence of the two species.

No abstract

The maximum entropy (MaxEnt) model for predicting the potential suitable habitat of species has been commonly employed in many ecological and biological applications by using presence-only occurrence records along with associated environmental factors. Parnassia wightiana, a perennial herb, is a cold-adapted plant distributed across three diversity hotspots in China, including the Hengduan Range, Central China and the Lingnan region. The MaxEnt model was used to simulate the historic, current and future distribution trends of P. wightiana, as well as to analyse its distribution pattern in each historical period and explore the causes of species distribution changes. The results of our analysis indicated that annual precipitation, annual temperature range and mean temperature of the warmest quarter were the key bioclimatic variables affecting the distribution of P. wightiana. Most temperate species retracted into smaller refugial areas during glacial periods and experienced range expansion during interglacial periods. Possible refugia of the species were inferred to be located in the Hengduan Range and Qinling Regions.