Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. Here, we report population-wide DNA sequencing of genomes, transcriptomes, and methylomes of wild Arabidopsis thaliana accessions. Single cytosine methylation polymorphisms are unlinked to genotype. However, the rate of linkage disequilibrium decay amongst differentially methylated regions targeted by RNA-directed DNA methylation is similar to the rate for single nucleotide polymorphisms. Association analyses of these RNA-directed DNA methylation regions with genetic variants identified 2,372 methylQTL, which revealed the first population estimate of genetically dependent methylation variation. Analysis of invariably methylated transposons and genes across this population indicates that loci targeted by RNA-directed DNA methylation are epigenetically reactivated during male gametogenesis, which facilitates their silencing across generations. RNA-seq from naturally-occurring Arabidopsis accessions
Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. Here, we report population-wide DNA sequencing of genomes, transcriptomes, and methylomes of wild Arabidopsis thaliana accessions. Single cytosine methylation polymorphisms are unlinked to genotype. However, the rate of linkage disequilibrium decay amongst differentially methylated regions targeted by RNA-directed DNA methylation is similar to the rate for single nucleotide polymorphisms. Association analyses of these RNA-directed DNA methylation regions with genetic variants identified 2,372 methylQTL, which revealed the first population estimate of genetically dependent methylation variation. Analysis of invariably methylated transposons and genes across this population indicates that loci targeted by RNA-directed DNA methylation are epigenetically reactivated during male gametogenesis, which facilitates their silencing across generations.
Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. MethylC-seq from naturally-occurring Arabidopsis accessions
Project description:Vaccines to prevent capsular group B meningococcal disease have been based on proteins, as the polysaccharide capsule was deemed unsuitable due to its similarity to human tissues. Outer membrane vesicle (OMV) vaccines have been targeted at specific capsular group B epidemics in Cuba, Norway, and New Zealand, with the major immunogen determined as porin A (PorA). Subcapsular protein vaccines aim to increase breadth of coverage of meningococcal strains, by the inclusion of protein variants from many different clonal complexes (ccs). Using scalable and portable genomic techniques, it is possible to study the diversity of OMV and subcapsular proteins in relevant meningococcal populations. Shotgun proteomics identified 461 proteins in the OMVs derived from NZ98/254, a component of the Bexsero® vaccine, with a complex proteome comprised of outer membrane proteins and proteins from other cellular compartments. Amino acid sequences for 24 selected proteins were catalogued within the PubMLST Neisseria database as part of the OMV peptide Typing (OMVT) scheme. Of the 24 proteins included, there was variation in the extent of diversity and association with ccs from the most conserved peptides FbpA (NEISp0578) and putative periplasmic proteins (NEISp1063) to the most diverse TbpA (NEISp1690). There were 1752 OMVTs identified amongst 2492/3506 isolates. OMVTs were further grouped into clusters (identical at ≥18 peptide sequences), 45.3% of isolates were assigned to one of 27 OMVT clusters. Both OMVTs and clusters were strongly associated with cc, genogroup and recombinant Bexsero® antigens. The OMVT scheme represents an open-access, web-based tool for the systematic analysis of the multiple components of OMV vaccines, demonstrating that combinations of OMV proteins exist in discrete, non-overlapping combinations associated with both genogroup and Bexsero® Antigen Sequence type (BAST). This highly structured population of disease-causing meningococci is consistent with proposed effects of host immune selection and competition between allelic variants on meningococcal population structure. This has implications for future vaccine assessment, and development, especially the choice of antigen combinations. The methodology is portable and will facilitate region-specific WGS interrogation, allowing informed choices about vaccine development or implementation.
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:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation.
Project description:Campylobacter jejuni has become the predominant cause of sheep abortions in the U.S. However, little is know about the genetic diversity among the isolates collected from different time periods. In this study, the genetic diversity of sheep aborion isolates of C. jejuni was investigated by Array-based CGH