Biology subjects

Schrey, A. W.

Publications and source records attributed to Schrey, A. W..

2 recordsLinked to original sources

bioRxiv2020

Inheritance of DNA methylation differences in the mangrove Rhizophora mangle

The capacity to respond to environmental challenges ultimately relies on phenotypic variation which manifests from complex interactions of genetic and non-genetic mechanisms through development. While we know something about genetic variation and structure of many species of conservation importance, we know very little about the non-genetic contributions to variation. Rhizophora mangle is a foundation species that occurs in coastal estuarine habitats throughout the neotropics where it provides critical ecosystem functions, and is potentially threatened by climate change. Several studies have documented landscape level patterns of genetic variation in this species, but we know virtually nothing about the inheritance of non-genetic variation. To assess one type of non-genetic variation, we examined the patterns of DNA sequence and DNA methylation in maternal plants and offspring from natural populations of R. mangle from the Gulf Coast of Florida. We used a reduced representation bisulfite sequencing approach (epi-genotyping by sequencing or epiGBS) to address the following questions: a) What are the levels of genetic and epigenetic diversity in natural populations of R. mangle? b) How are genetic and epigenetic variation structured within and among populations? c) How faithfully is epigenetic variation inherited? We found low genetic diversity but high epigenetic diversity from natural populations of maternal plants in the field and that a large portion (up to ~25%) of epigenetic differences among offspring grown in common garden was explained by maternal family. Therefore, epigenetic variation could be an important source of response to challenging environments in the genetically depauperate populations of this foundation species.

genomics↗

bioRxiv2020

Epigenetic Potential and DNA Methylation in an Ongoing House Sparrow (Passer domesticus) Range Expansion

During range expansions, epigenetic mechanisms may mediate phenotypic responses to environmental cues, enabling organisms to adjust to novel conditions at novel sites. Here, we predicted that the number of CpG sites within the genome, one form of epigenetic potential, would be important for success during range expansions because DNA methylation can modulate gene expression and hence facilitate adaptive plasticity. Previously, we found that this same form of epigenetic potential was higher in introduced compared to native populations of house sparrows (Passer domesticus) for two immune genes (Toll-like receptors 2A and 4). Here, we took a reduced-representation sequencing approach (ddRadSeq and EpiRadSeq) to investigate how CpG site number, as well as resultant DNA methylation, varied across five sites in the [~]70 year-old Kenyan house sparrow range expansion. We found that the number of CpG sites increased towards the vanguard of the invasion, even when accounting for variation in genetic diversity among sites. This pattern was driven by more losses of CpG sites towards the core of the invasion (the initial site of introduction). Across all sequenced loci, DNA methylation decreased but became more variable towards the range-edge. However, in the subset CpG sites proximal to mutated CpG sites, DNA methylation increased and variation declined. These results indicate that epigenetic potential influenced the Kenyan house sparrow range expansion, likely by providing greater phenotypic plasticity which is genetically assimilated as populations adapt to local conditions. Similar mechanisms might underlie the successes and failures of other natural and anthropogenic range expansions.

evolutionary biology↗