Biology subjects

Adam J Bewick

Publications and source records attributed to Adam J Bewick.

4 recordsLinked to original sources

bioRxiv2016

The evolution of DNA methylation and its relationship to sociality in insects

DNA methylation contributes to gene and transcriptional regulation in eukaryotes, and therefore has been hypothesized to facilitate the evolution of flexible traits such as sociality in insects. However, DNA methylation is sparsely studied in insects. Therefore, we documented patterns of DNA methylation across a wide diversity of insects. Furthermore, we tested the hypothesis that the DNA methylation system will be associated with presence/absence of sociality among insects. We also predicted that underlying enzymatic machinery is concordant with patterns of DNA methylation. We found DNA methylation to be widespread, detected in all orders examined except Diptera (flies). Whole genome bisulfite sequencing showed that orders differed in levels of DNA methylation. Hymenopteran (ants, bees, wasps and sawflies) had some of the lowest levels, including several potential losses. Blattodea (cockroaches) show all possible patterns, including a potential loss of DNA methylation in a eusocial species whereas solitary species had the highest levels. Phylogenetically corrected comparisons revealed no evidence that supports evolutionary dependency between sociality and DNA methylation. Species with DNA methylation do not always possess the typical enzymatic machinery. We identified a gene duplication event in the maintenance DNA methyltransferase 1 (DNMT1) that is shared by some hymenopteran, and paralogs have experienced divergent, non-neutral evolution. This diversity and non-neutral evolution of underlying machinery suggests alternative DNA methylation pathways may exist. Altogether, DNA methylation is highly variable in insects and is not a universal driver of social behavior. Future, functional studies are required to advance our understanding of DNA methylation in insects.

Evolutionary Biology↗

bioRxiv2016

Widespread natural variation of DNA methylation within angiosperms

To understand the variation in genomic patterning of DNA methylation we compared methylomes of 34 diverse angiosperm species. By analyzing whole-genome bisulfite sequencing data in a phylogenetic context it becomes clear that there is extensive variation throughout angiosperms in gene body DNA methylation, euchromatic silencing of transposons and repeats, as well as silencing of heterochromatic transposons. The Brassicaceae have reduced CHG methylation levels and also reduced or loss of CG gene body methylation. The Poaceae are characterized by a lack or reduction of heterochromatic CHH methylation and enrichment of CHH methylation in genic regions. Reduced CHH methylation levels are found in clonally propagated species, suggesting that these methods of propagation may alter the epigenomic landscape over time. These results show that DNA methylation patterns are broadly a reflection of the evolutionary and life histories of plant species.

Plant Biology↗

bioRxiv2016

On the Origin and Evolutionary Consequences of Gene Body DNA Methylation

In plants, CG DNA methylation is prevalent in the transcribed regions of many constitutively expressed genes (\"gene body methylation; gbM\"), but the origin and function of gbM remain unknown. Here we report the discovery that Eutrema salsugineum has lost gbM from its genome, the first known instance for an angiosperm. Of all known DNA methyltransferases, only CHROMOMETHYLASE 3 (CMT3) is missing from E. salsugineum. Identification of an additional angiosperm, Conringia planisiliqua, which independently lost CMT3 and gbM supports that CMT3 is required for the establishment of gbM. Detailed analyses of gene expression, the histone variant H2A.Z and various histone modifications in E. salsugineum and in Arabidopsis thaliana epiRILs found no evidence in support of any role for gbM in regulating transcription or affecting the composition and modifications of chromatin over evolutionary time scales.

Plant Biology↗

bioRxiv2015

FASTmC: a suite of predictive models for non-reference-based estimations of DNA methylation

We describe a suite of predictive models, coined FASTmC, for non-reference, cost-effective exploration and comparative analysis of context-specific DNA methylation levels. Accurate estimations of true DNA methylation levels can be obtained from as few as several thousand short-reads generated from whole genome bisulfite sequencing. These models make high-resolution time course or developmental, and large diversity studies practical regardless of species, genome size and availability of a reference genome.

Bioinformatics↗