Progress on miRNA in giant panda (Ailuropoda melanoleuca).

MicroRNAs (miRNAs), a family of endogenous non-coding RNAs with a length of about 22 nucleotides, are widely found in eukaryotes. miRNAs can affect gene expression through specific bindings with mRNAs of target genes and participate in the regulation of a variety of biological processes. Giant panda is not only a unique rare animal in China, but also the focus of attention on wildlife preservation worldwide. In recent years, with the popularization of next-generation sequencing (NGS) technology, miRNAs in giant panda have been discovered and identified one after another. In this review, we focus on the research progress on miRNAs in giant panda, involved in immune response, mammary gland development, sperm freezing tolerance and other biological processes, and then discuss future research directions of miRNAs in giant panda, and thus providing the scientific references and new ideas for studying the regulatory mechanisms of miRNAs and promoting the breeding and protection of giant panda.

Genetic structure in dwarf bamboo (Bashania fangiana) clonal populations with different genet ages.

Amplified fragment length polymorphism (AFLP) fingerprints were used to reveal genotypic diversity of dwarf bamboo (Bashania fangiana) clonal populations with two different genet ages (≤30 years versus >70 years) at Wolong National Natural Reserve, Sichuan province, China. We generated AFLP fingerprints for 96 leaf samples, collected at 30 m intervals in the two populations, using ten selective primer pairs. A total of 92 genotypes were identified from the both populations. The mean proportion of distinguishable genotypes (G/N) was 0.9583 (0.9375 to 0.9792) and Simpson's index of diversity (D) was 0.9982 (0.9973 to 0.9991). So, two B. fangiana populations were multiclonal and highly diverse. The largest single clone may occur over a distance of about 30 m. Our results demonstrated that the genotypic diversity and genet density of B. fangiana clonal population did not change significantly (47 versus 45) with genet aging and low partitioned genetic differentiation was between the two populations (Gst = 0.0571). The analysis of molecular variance consistently showed that a large proportion of the genetic variation (87.79%) existed among the individuals within populations, whereas only 12.21% were found among populations. In addition, the high level of genotypic diversity in the two populations implies that the further works were needed to investigate the reasons for the poor seed set in B. fangiana after flowering.

[Effects of wilderness-training Ailuropoda melanoleuca's feeding and artificial harvesting on population structure of Fargesia robusta clone].

From 2003 to 2007, the methods of plot sampling and positioning observation were adopted to investigate the population density, basal diameter, and plant height of Umbrella bamboo (Fargesia robusta) clone in the Wolong Natural Reserve of China. In the meantime, the effects of wilderness-training Ailuropoda melanoleuca's feeding and artificial harvesting on the population regeneration of the clone were studied, and the responses of the population structure (age-, size-, and height-class distribution) to different management modes (A. melanoleuca's feeding, artificial harvesting, control) were approached with the scale- and shape-parameters of Weibull distribution function. The results showed that under the same F. robusta clone population density and the same environmental conditions (P>0.05), A. melanoleuca's feeding and artificial harvesting promoted the clone regeneration. After 3 years natural restoration, the population density of the clone tended to be equal to the control, and came to a steady state (P>0.05). The curves of size- and height-class distribution as well as the scale- and shape-parameters had no significant differences between A. melanoleuca's feeding plot and control plot. The curves of size- and height-class distribution in artificial harvesting plot were in converse "J" shape, and the values of the scale- and shape-parameters were significantly lower than those in the other two plots (P<0.05). The young and adult bamboos in artificial harvesting plot were far poor in shoot quality, and A. melanoleuca rejected to feed with them.