The Apollo butterfly, Parnassius glacialis, is one of the most charming members of its genus and includes two subspecies locally distributed in montane areas of south-central China and Japan. In this study, we investigated the genetic structure and demographic history of P. glacialis by analyzing partial sequences of four mitochondrial genes and nuclear single nucleotide polymorphisms (SNPs) via genotyping-by-sequencing (GBS) of samples from nearly the entire known distributional range in China. The mitochondrial DNA (mtDNA) data demonstrated that a total of 39 haplotypes were present, and the species was estimated to have diverged about 0.95 million years ago during the middle Pleistocene transition into two main clades that likely formed during the Kunlun-Huanghe tectonic movement. The two clades then dispersed independently in distinct geographic areas alongside the mountainous routes in central and southern China, most likely driven by the Pleistocene glacial-interglacial cycles. Nuclear SNP analysis was generally congruent with mtDNA results at the individual level. A minor incongruence of genetic structures that was detected between mtDNA and nuclear SNP data from the Laojunshan and Tiantangzhai populations was likely due to secondary contact and male-biased dispersal. Our work demonstrates that complicated dispersal-vicariance evolutionary processes likely led to the current geographic distribution of P. glacialis in China, particularly the uplift of the Qinghai-Tibet Plateau and related climatic oscillations during the Quaternary period.

We studied 239 imagoes of 12 Parnassius species collected from the mountains of the Qinghai–Tibet Plateau (QTP) and its neighbouring areas in China. We selected three mitochondrial gene (COI, ND1, and ND5) sequences, along with the homologous gene sequences of other Parnassius species from GenBank, to reconstruct the phylogenetic tree and biogeographic history of this genus. Our results show that Parnassius comprises eight monophyletic subgenera, with subgenus Parnassius at the basal position; the genus crown group originated during the Middle Miocene (ca. 16.99 Ma), and species diversification continued during sustained cooling phases after the Middle Miocene Climate Optimum (MMCO) when the QTP and its neighbouring regions experienced rapid uplift and extensive orogeny. A phylogenetic network analysis based on transcriptomes from GenBank suggests that ancient gene introgression might have contributed to the spread of the Parnassius genus to different altitudes. Ancestral area reconstruction indicates that Parnassius most likely originated in West China (QTP and Xinjiang) and then spread to America in two dispersal events as subgenera Driopa and Parnassius, along with their host plants Papaveraceae and Crassulaceae, respectively. Our study suggests that extensive mountain-building processes led to habitat fragmentation in the QTP, leading to the early diversification of Parnassius, and climate cooling after MMCO was the driving mechanism for the dispersal of Parnassius butterflies from West China to East Asia, Europe, and North America.

In this paper, the starch was firstly modified by quaternary reagent to obtain cationic starch. Then self-assembled folate-biotin-quaternized starch nanoparticles were prepared by a one-pot synthesis via N,N'-dicyclohexylcarbodiimide/N-hydroxysuccinimide/4-dimethylaminopyridine-mediated esterification reaction. The physicochemical properties of the prepared folate-biotin-quaternized starch nanoparticles were characterized. The average diameter of folate-biotin-quaternized starch nanoparticles was 109 nm with polydispersity index of 0.183 and zeta potential of 28.59 mV. The folate-biotin-quaternized starch nanoparticles were used as co-carrier of siRNA and doxorubicin with satisfactory drug loading capacity (6.98%) and encapsulation efficiency (69.66 %), and siRNA could be efficiently encapsulated at 40/1 weight ratio of doxorubicin/folate-biotin-quaternized starch nanoparticles to siRNA. The folate-biotin-quaternized starch nanoparticles could effectively protect siRNA from degradation of serum RNAase for up to 48 h. The release characteristics of doxorubicin and siRNA from folate-biotin-quaternized starch nanoparticles were studied in different pH environment and the release behaviors of two drugs were all pH sensitive. The folate-biotin-quaternized starch nanoparticles as a potential co-carrier of anticancer agents and gene drugs was expected to achieve future practical application in vitro and in vivo.

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