Project description:Female adult spongy moths vary in their flight capacity depending upon their origin and subspecies. Asian spongy moth (Lymantria dispar asiatica) females (such as the RM strain here) can fly whereas European spongy moth (Lymantria dispar dispar) females cannot (such as the CT strain here). We hypothesized that the genetic origins of these differences in flight capacity would be reflected in differences in gene expression during metamorphosis (the pupal stage). To test this, we compared the gene expression at days 1, 3, 5, 8, and 11 of pupal development of female pupae from CT and RM strains.
Project description:Laser Capture Microdissection (LCM) was used for expression analysis of three contrasted fungal tissues of uredinia corresponding respectively to spores and sporogenous hyphae, fungal structures in the spongy mesophyll and fungal infection structures in the palisade mesophyll. The array probes were designed from gene models taken from the Joint Genome Institute (JGI, Department of Energy) Melampsora larici-populina genome sequence version 1. The aim of this study was to identify tissue-specific gene expression to gain insights into the genes specifically associated with the biotrophic phase and the sporulation phase of the rust fungus. We performed 9 hybridizations (NimbleGen) with samples derived from Laser Capture Microdissection (LCM) of three contrasted fungal tissues of uredinia, corresponding respectively to spores and sporogenous hyphae, fungal structures in the spongy mesophyll and fungal infection structures in the palisade mesophyll. Three replicates per tissue. All samples were labeled with Cy3.
Project description:Eukaryotes gene expression of mRNA and protein is a basic cellular activity and regulated by multiple process, yet the expression patterns at these two levels and their genetic and evolutionary determinants remain undefined in plants. Here, using RNA-sequencing and TMT labeled LC-MS/MS analysis, we investigated the genome-wide variation of mRNA and protein expression in rice subspecies japonica C92, indica MH63 and their F1 hybrid. Different expression patterns of mRNA and protein between C92 and MH63 were linked to distinct functional categories. Genes with consistent divergence of mRNA and protein expression between subspecies tend to be regulated by cis effect and had higher sequence variation in nonsynonymous sites. Population differentiation (FST) analysis showed that genes with conserved expression of either mRNA or protein in C92 and MH63 were more likely to be under purify selection, while genes with consistent divergence in mRNA or protein expression were more likely to be under positive selection, especially in their nonsynonymous site have high frequency of positive selected genes that changed their protein sequence by nonsynonymous mutation. Furthermore, oxidative stress response genes were enriched in genes with consistent divergence of expression, and showed higher sequence variation in nonsynonymous sites and are more likely to be positive selected in evolution. These results suggested that cis-regulation with high nonsynonymous-variation was evolutionarily important feature to shape divergent expression patterns of mRNA and protein and may contribute to diversity in oxidative stress response between rice subspecies.
Project description:To understand the evolution of imprinting mechanisms in the rice species Oryza sativa, we analyzed DNA methylation, transcription and small RNA expression in embryo and endosperm. Cultivars chosen to represent the genetic diversity of cultivated Oryza sativa comprised Nipponbare and Kitaake of the japonica subspecies, and IR64 and 93-11 cultivars of the indica subspecies. While imprinted expression is generally conserved among rice cultivars, approximately 10% of imprinted genes show imprinting divergence across the four cultivars. Analyses of DNA methylation and small RNAs revealed that small RNA producing loci are closely associated with genic regions and four times more likely to be imprinted than genes. However, imprinting divergence most often correlated with DNA methylation epimutations. Correlative epialleles were largely stable within subspecies. Small indels and transposable element insertions were found at half of the epimutated loci and associated with imprinting divergence at half of the remaining loci. Correlating epigenetic and genetic variation occurred at key regulatory regions – the promoter and transcription start site of maternally-biased genes, and the promoter and gene body of paternally-biased genes. Our results reinforce models for the role of maternal-specific DNA hypomethylation in imprint formation at both maternally and paternally biased genes, and highlight the role of transposition events and epimutation in rice imprinting evolution.
Project description:Plumage color plays a prominent role in reproductive isolation and thus understanding the genetic basis of pigmentation patterns can provide critical insight into speciation. Subspecies of the dark-eyed junco (Junco hyemalis) show marked differences in melanic plumage coloration known to have evolved rapidly since the Last Glacial Maximum just 18,000 years ago. To understand this rapid radiation we studied the pigment composition and the genetic basis of coloration in two divergent subspecies, the slate-colored and Oregon juncos. We used HPLC and light microscopy to investigate pigment deposition patterns in feathers from four body areas. RNA-seq data generated under common garden experimental conditions were then used to compare the relative roles of differential gene expression in growing feathers and sequence divergence in loci expressed during feather development. Junco feathers were found to differ in eumelanin and pheomelanin content and distribution, producing a range of black, gray and brown colors. Transcriptomic data revealed marked regulatory differences among subspecies and among body-parts within subspecies in known melanin-pathway genes (including PMEL, TYR, TYRP1, OCA2, MLANA), but also in several novel or poorly known loci (EDAR, VPS33B, HPS1). Within subspecies, lighter feathers expressed less melanin synthesis genes, more ASIP, and showed differential expression of Wnt signaling genes. Feathers from different body regions also showed differential expression of Hox genes. The two subspecies differed in expression of ASIP and three other genes (MFSD12, KCNJ13, HAND2) previously associated with color development. Sequence variation in the expressed genes was not related to color differences between junco subspecies. Our findings suggest that differential expression of a few genes can account for marked differences in plumage color and pattern, a mechanism that can account for the rapid diversification of juncos. Several novel candidate pigmentation genes found in juncos may contribute to the expression of melanic coloration in other vertebrates.
Project description:We studied the evolution of alternative splicing in the early stages of species divergence in the house mouse. We sequenced the testis transcriptomes of three Mus musculus subspecies and Mus spretus using Illumina technology. On the basis of a genome-wide analysis of read coverage differences among subspecies, we identified several hundred candidate alternatively spliced regions.
Project description:Laser Capture Microdissection (LCM) was used for expression analysis of three contrasted fungal tissues of uredinia corresponding respectively to spores and sporogenous hyphae, fungal structures in the spongy mesophyll and fungal infection structures in the palisade mesophyll. The array probes were designed from gene models taken from the Joint Genome Institute (JGI, Department of Energy) Melampsora larici-populina genome sequence version 1. The aim of this study was to identify tissue-specific gene expression to gain insights into the genes specifically associated with the biotrophic phase and the sporulation phase of the rust fungus.
Project description:Here we introduce a test for lineage-specific selection of cis-regulation that can be applied to any gene set of interest. Applying the test to hundreds of gene sets in two diverged subspecies of mouse, we find evidence for selection acting on the cis-regulation of several functional classes, including those involved in both physiology (e.g. mitochondria-related genes and growth regulators) and behavior (e.g. locomotory-related genes and memory-related genes). These positively selected gene sets implicate potential targets of positive selection that are supported by quantitative trait loci, and accurately predict a number of phenotypic differences between the two subspecies, suggesting that the divergence in these traits may have been driven by adaptive evolution.