Comparative transcriptome analysis reveals candidate genes related to the sex differentiation of Schisandra chinensis.

Schisandra chinensis is a monoecious plant with unisex flowers. The fruit of S. chinensis is of high medical with economic value. The yield of S. chinensis fruit is related to the ratio of its female and male flowers. However, there is little research on its floral development and sex differentiation. To elucidate the possible mechanism for the sex differentiation of S. chinensis, we collected 18 samples of female and male flowers from three developmental stages and performed a comparative RNA-seq analysis aimed at identifying differentially expressed genes (DEGs) that may be related to sex differentiation. The results showed 936, 7179, and 6890 differentially expressed genes between female and male flowers at three developmental stages, respectively, and 466 candidate genes may play roles in sex differentiation. KEGG analysis showed genes involved in the flavonoid biosynthesis pathway and DNA replication pathway were essential for the development of female flowers. 51 MADS-box genes and 10 YABBY genes were identified in S. chinensis. The DEGs analysis indicated that MADS-box and YABBY genes were strongly related to the sex determination of S. chinensis. RT-qPCR confirmed the RNA-seq results of 20 differentially expressed genes, including three male-biased genes and 17 female-biased genes. A possible regulatory model of sex differentiation in S. chinensis was proposed according to our results. This study helps reveal the sex-differentiation mechanism of S. chinensis and lays the foundation for regulating the male-female ratio of S. chinensis in the future.

Comparative genomics of widespread and narrow-range white-bellied rats in the Niviventer niviventer species complex sheds light on invasive rodent success.

Widespread species that inhabit diverse environments possess large population sizes and exhibit a high capacity for environmental adaptation, thus enabling range expansion. In contrast, narrow-range species are confined to restricted geographical areas and are ecologically adapted to narrow environmental conditions, thus limiting their ability to expand into novel environments. However, the genomic mechanisms underlying the differentiation between closely related species with varying distribution ranges remain poorly understood. The Niviventer niviventer species complex (NNSC), consisting of highly abundant wild rats in Southeast Asia and China, offers an excellent opportunity to investigate these questions due to the presence of both widespread and narrow-range species that are phylogenetically closely related. In the present study, we combined ecological niche modeling with phylogenetic analysis, which suggested that sister species cannot be both widespread and dominant within the same geographical region. Moreover, by assessing heterozygosity, linkage disequilibrium decay, and Tajima's D analysis, we found that widespread species exhibited higher genetic diversity than narrow-range species. In addition, by exploring the "genomic islands of speciation", we identified 13 genes in highly divergent regions that were shared by the two widespread species, distinguishing them from their narrow-range counterparts. Functional annotation analysis indicated that these genes are involved in nervous system development and regulation. The adaptive evolution of these genes likely played an important role in the speciation of these widespread species.

Molecular Structure and Phylogenetic Analyses of the Complete Chloroplast Genomes of Three Medicinal Plants Conioselinum vaginatum, Ligusticum sinense, and Ligusticum jeholense.

Most plants of Ligusticum have an important medicinal and economic value with a long history, Ligusticum sinense and L. jeholense ("Gaoben") has long been used in traditional Chinese medicine for the treatment of carminative, dispelling cold, dehumidification, and analgesia. While in the market Conioselinum vaginatum (Xinjiang Gaoben) is substitution for Gaoben, and occupies a higher market share. These three Gaoben-related medicinal materials are similar in morphology, and are difficult to distinguish from each other by the commonly used DNA barcodes. The chloroplast genome has been widely used for molecular markers, evolutionary biology, and barcoding identification. In this study, the complete chloroplast genome sequences of C. vaginatum, L. sinense, and L. jeholense were reported. The results showed that the complete chloroplast genomes of these three species have typical quadripartite structures, which were comprised of 148,664, 148,539, and 148,497 bp. A total of 114 genes were identified, including 81 protein-coding genes (PCGs), 29 tRNA genes, and four rRNA genes. Our study indicated that highly variable region ycf2-trnL and accD-ycf4 that can be used as specific DNA barcodes to distinguish and identify C. vaginatum, L. sinense, and L. jeholense. In addition, phylogenetic study showed that C. vaginatum nested in Ligusticum and as a sister group of L. sinense and L. jeholense, which suggested these two genera are both in need of revision. This study offer valuable information for future research in the identification of Gaoben-related medicinal materials and will benefit for further phylogenetic study of Apiaceae.

[Vestibulotomy about the displaced facial nerve].

OBJECTIVE: To investigate the feasibility of vestibulotomy above the displaced facial nerve. METHODS: From January 2000 to January 2002, eight patients with severe congenital conductive hearing loss underwent the vestibulotomy above displaced facial nerve and reconstruction of the ossicular chain with a total ossicular replacement prosthesis, which all for the congenital middle ear deformity and the facial nerve overhang and concealed the oval window niche or lied inferior to the oval window. In four of eight cases, the facial nerve was transposed in order to access the oval window niche. RESULTS: Hearing of this patients improved 15 dB in 2 ears, 16-25 dB in 3 ears and 26 dB or more in 3 ears. In no case was there a postoperative facial paresis. With 4 months to 28 months follow-up, the postoperative hearing gain was stable. CONCLUSIONS: Vestibulotomy above displacement of the facial nerve allows a final chance of achieving serviceable hearing through surgery. The lack of facial nerve injury and the potential for hearing restoration make this procedure feasible in otherwise marginal or poor surgical candidates.