Project description:The Malayan pangolin (Manis javanica), an unusual mammal that is a scale-covered, toothless specialist myrmecophage, is maintained primarily through captive breeding in China. Maintaining this species in captivity is a significant challenge partly because little is known about its behavior and reproduction. The molecular mechanisms of its digestive system play a key role in the feeding and dietary husbandry of pangolins in captivity. Here, we performed the first large-scale sequencing of M. javanica transcriptomes from three digestive organs—the salivary glands, liver, and small intestine—by using Illumina HiSeq technology- to provides useful genetic resources for future functional work that may be relevant for the maintenance of captive pangolins.
Project description:Eucalyptus urophylla is a commercially important wood crop plantation species due to its rapid growth, biomass yield, and use as bioenergy feedstock. We characterized the genetic diversity and population structure of 332 E. urophylla individuals from 19 geographically defined E. urophylla populations with a reliability of 14,468 single nucleotide polymorphisms (SNPs). We compared the patterns of genetic variation among these 19 populations. High levels of genetic diversity were observed throughout the 19 E. urophylla populations based on genome-wide SNP data (HE=0.2677 to 0.3487). Analysis with STRUCTURE software, Principal component analysis (PCA) and a neighbor-joining (NJ) tree indicated that E. urophylla populations could be divided into three groups, and moderate and weak population structure was observed with pairwise genetic differentiation (FST) values ranging from −0.09 to 0.074. The low genetic diversity and shallow genetic differentiation found within the 19 populations may be a consequence of their pollination system and seed dispersal mechanism. In addition, 55 core germplasms of E. urophylla were constructed according to the genetic marker data. The genome-wide SNPs we identified will provide a valuable resource for further genetic improvement and effective use of the germplasm resources.
Project description:Background: Aquaculture of the black tiger prawn Penaeus monodon remains severely constrained by an almost total dependence on wild-caught broodstock. Reliance on wild-caught broodstock stems, for the most part, from reduced reproductive potential of captive-reared females. Reproductive performance of captive-reared females is usually characterised by longer latency period, lower egg production, egg hatch rates and post-larval survivorship compared with their wild-caught counterparts. Improved understanding of the cellular and associated molecular events occurring during peneaid ovarian maturation could therefore be fundamental to improving reproductive success of captive-reared animals. Methodology/Principle Findings: In support of other studies, our histological analyses of developing oocytes revealed differences between wild-caught and captive-reared P. monodon, including reduced lipid accumulation in oocytes of captive-reared animals. We have employed oligonucleotide microarray analysis to compare expression profiles of genes involved in ovarian maturation among wild-caught and captive-reared animals. Custom oligonucleotide microarrays were constructed and screened with transcripts derived from the ovary, cephalothorax and eyestalk from animals of all ovarian maturation stages. Ovarian maturation-related differential expression patterns were observed for 111 transcripts, with 53 transcripts displaying differential expression between wild-caught and captive-reared animals. Notably transcripts encoding vitellogenin - the major egg yolk protein precursor, and a lipid storage droplet protein (which we named pmLSD) which is involved in lipid accumulation, were found to be more highly expressed in wild-caught animals. pmLSD transcripts localise to pre-vitellogenic oocytes of wild-caught animals and the pmLSD protein is exclusively localised to the surface of lipid droplets of oocytes at vitellogenic and cortical rod stages. We have employed oligonucleotide microarray analysis to compare expression profiles of genes involved in ovarian maturation among wild-caught and captive-reared animals. Target preparation and microarray hybridisation. Ovarian RNA samples from nine wild-caught animals representing six ovarian maturation stages (P, 2, 24, V, R, E) were used in microarray hybridisations. Similarly, RNA samples from three captive-reared animals representing four maturation stages (P, 24, V, E) were used in microarray hybridisations. For wild-caught animals, samples from each ovarian maturation stage were pooled into groups of four and five, enabling two hybridisations. For captive-reared animals, samples from each ovarian maturation stage from all three animals were pooled enabling one hybridisation for each stage. Importantly, as the four stages for captive-reared animals were (1) pre-ablation pre-vitellogenic, (2) post-ablation pre-vitellogenic, (3) post-ablation vitellogenic, (4) post-ablation vitellogenic with cortical rods, this arrangement allowed for 2 samples of captive-reared pre-vitellogenic and 2 samples of captive-reared vitellogenic, thereby enabling t-tests between samples, while also allowing analysis across the whole 4 stages via cluster analysis. All hybridisations were single channel hybridisations conducted using equal amounts of RNA pooled from each individual.