Abstracts Many endangered species have small population sizes, with less than 10 remaining individuals in some extreme situations. Although the consequences of a small population size have received considerable research attention, few studies have examined the fate of extremely rare plants. Ostrya rehderiana is one such species, with only 5 naturally-regenerated surviving individuals and less than 150 artificially-regenerated progeny. Using amplified fragment length polymorphisms (AFLPs), we found that there was a low percentage of polymorphic loci but moderate heterozygosity in the 5 wild individuals. A severe decline in genetic diversity was observed in the progeny, with a decrease of 36.7% in heterozygosity and of 12% in the number of markers that were amplified per individual compared with the parental generation, a result which was caused by genetic drift and inbreeding. The effective population size was estimated to be 1. A significant positive relationship between parental genetic dissimilarity and the number of surviving offspring was observed, which indicated that inbreeding depression might have purged more inbred offspring. Implications for protection and recovery of the genetic variation of extremely rare plants, such as O. rehderiana, are proposed.

Long dormancy period of seeds limits the large-scale artificial cultivation of the scarce Paris polyphylla var. yunnanensis, an important traditional Chinese medicine. Characterizing miRNAs and their targets is crucial to understanding the role of miRNAs during seed dormancy in this species. Considering the limited genome information of this species, we first sequenced and assembled the transcriptome data of dormant seeds and their seed coats as the reference genome. A total of 146,671 unigenes with an average length of 923 bp were identified and showed functional diversity based on different annotation methods. Two small RNA libraries from respective seeds and seed coats were sequenced and the combining data indicates that 263 conserved miRNAs belonging to at least 83 families and 768 novel miRNAs in 1174 transcripts were found. The annotations of the predicted putative targets of miRNAs suggest that these miRNAs were mainly involved in the cell, metabolism and genetic information processing by direct and indirect regulation patterns in dormant seeds of P. polyphylla var. yunnanensis. Therefore, we provide the first known miRNA profiles and their targets, which will assist with further study of the molecular mechanism of seed dormancy in P. polyphylla var. yunnanensis.

Machine intelligence (MI), including machine learning and deep learning, have been regarded as promising methods to reduce the prohibitively high cost of drug development. However, a dilemma within MI has limited its wide application: machine learning models are easier to interpret but yield worse predictive performance than deep learning models. Therefore, we propose a pipeline called Class Imbalance Learning with Bayesian Optimization (CILBO) to improve the performance of machine learning models in drug discovery. To demonstrate the efficacy of the CILBO pipeline, we developed an example model to predict antibacterial candidates. Comparison of the antibacterial prediction performance between our model and a well-known deep learning model published by Stokes et al. suggests that our model can perform as well as the deep learning model in drug activity prediction. The CILBO pipeline we propose provides a simple, alternative approach to accelerate preliminary screenings and decrease the cost of drug discovery.

Regional gender differences in autosomal chromosome disorders have been observed repeatedly. However, the corresponding diversity changes remain unconfirmed. By analyzing previously published thalassemia data from the Dai people in Dehong and Xishuangbanna (two regions in Yunnan Province, China), we found that several sequence types, including HBA CNV and HBB mutations, significantly depend on gender in Xishuangbanna but not in Dehong. With the supportive evidence from previous researches, we accept that some certain mutations depend on gender regionally. This association seems peculiar. It is among one common people on a small geographical scale, while other recorded thalassemia gender difference varies by ethnics and continent.

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