Biology subjects

Forester, B. R.

Publications and source records attributed to Forester, B. R..

6 recordsLinked to original sources

bioRxiv2025

Summer rainfall drives adaptation with gene flow in a widespread butterfly

Understanding how environmental variation interacts with gene flow to shape population genomic patterns is a central goal in evolutionary biology. We investigated how geographic and environmental differences impact genomic variation in the clouded sulfur butterfly (Colias philodice eriphyle) by conducting whole-genome resequencing across replicated transects consisting of paired high- and low-elevation sites on both sides of a major mountain range. Despite sampling across steep environmental gradients, we found no evidence of discrete population structure, indicating high connectivity across the region. Nonetheless, significant isolation by distance - strongest in eastern populations - revealed that geographic distance still imposes limits on gene flow, and genetic diversity was also elevated in the east. Genotype-environment association analyses identified more than 16,000 loci associated with elevation, precipitation, and solar radiation. Our redundancy analysis identified precipitation as the strongest predictor of adaptive genomic differentiation, and candidate genes included those linked to melanization and thermoregulation (e.g., TH and yellow). These results demonstrate that even in a largely panmictic population, environmental variation can maintain regional-scale signals of local adaptation. Because insects are declining globally and remain underrepresented in genomic monitoring, conducting whole-genome analyses in a widespread species provides valuable context for assessing how insects today persist across such diverse landscapes and their potential for withstanding future environmental change.

evolutionary biology↗

bioRxiv2024

Abnormal activation of the mineralocorticoid receptor in the aldosterone-sensitive distal nephron contributes to fructose-induced salt-sensitive hypertension

Fructose high-salt (FHS) diets increase blood pressure (BP) in an angiotensin II (Ang II)-dependent manner. Ang II stimulates aldosterone release, which, by acting on the mineralocorticoid receptor (MR), regulates Na+ reabsorption by the aldosterone-sensitive distal nephron (ASDN). The MR can be transactivated by glucocorticoids, including those locally produced by 11{beta}-HSD1. The epithelial sodium channel (ENaC) is a key transporter regulated by MRs. We hypothesized that fructose-induced salt-sensitive hypertension depends in part on abnormal activation of MRs in the ASDN with consequent increases in ENaC expression. We found that aldosterone-upregulated genes in mice ASDN, significantly overlapped with 74 genes upregulated by FHS in the rat kidney cortex (13/74; p[≤]1x10-8), and that these 74 genes are prominently expressed in rat ASDN cells. Additionally, the average z-score expression of mice-aldosterone-upregulated genes is highly correlated with FHS compared to glucose high-salt (GHS) in the rat kidney cortex (Pearson correlation; r=0.66; p[≤]0.005). There were no significant differences in plasma aldosterone concentrations between the FHS and GHS. However, 11{beta}-HSD1 transcripts were upregulated by FHS (log2FC=0.26, p[≤]0.02). FHS increased BP by 23{+/-}6 mmHg compared to GHS, and blocking MRs with eplerenone prevented this increase. Additionally, inhibiting ENaC with amiloride significantly reduced BP in FHS from 148{+/-}6 to 134{+/-}5 mmHg (p[≤]0.019). Compared to GHS, FHS increased total and cleaved ENaC protein by 89{+/-}14 % (p[≤]0.03) and 47{+/-}16 % (p[≤]0.01) respectively. FHS did not change {beta}- or {gamma}-subunit expression. These results suggest that fructose-induced salt-sensitive hypertension depends, in part, on abnormal Na+ retention by ENaC, resulting from the activation of MRs by glucocorticoids.

physiology↗

bioRxiv2023

Life on the edge: a new toolbox for population-level climate change vulnerability assessments

O_LIGlobal change is impacting biodiversity across all habitats on earth. New selection pressures from changing climatic conditions and other anthropogenic activities are creating heterogeneous ecological and evolutionary responses across many species geographic ranges. Yet we currently lack standardised and reproducible tools to effectively predict the resulting patterns in species vulnerability to declines or range changes. C_LIO_LIWe developed an informatic toolbox that integrates ecological, environmental and genomic data and analyses (environmental dissimilarity, species distribution models, landscape connectivity, neutral and adaptive genetic diversity and genotype-environment associations) to estimate population vulnerability. In our toolbox, functions and data structures are coded in a standardised way so that it is applicable to any species or geographic region where appropriate data are available, for example individual or population sampling and genomic datasets (e.g. RAD-seq, ddRAD-seq, whole genome sequencing data) representing environmental variation across the species geographic range. C_LIO_LIWe apply our toolbox to a georeferenced genomic dataset for the East African spiny reed frog (Afrixalus fornasini) to predict population vulnerability, as well as demonstrating that range loss projections based on adaptive variation can be accurately reproduced using data for two European bat species (Myotis escalerai, and M. crypticus). C_LIO_LIOur framework sets the stage for large scale, multi-species genomic datasets to be leveraged in a novel climate change vulnerability framework to quantify intraspecific differences in genetic diversity, local adaptation, range shifts and population vulnerability based on exposure, sensitivity, and range shift potential. C_LI

evolutionary biology↗

bioRxiv2020

Environmental Drivers of Variation in Labial Teeth Number in Ascaphus Tadpoles

Morphological variation is often maintained by complex and interrelated factors, complicating the identification of underlying drivers. Tadpole oral morphology is one such trait that may be driven by the independent and interacting effects of the environment and variation in developmental processes. Although many studies have investigated tadpole oral morphological diversity among species, few have sought to understand the drivers that underlie intraspecific variation. In this study, we investigated potential drivers of labial tooth number variation among populations of two species of tailed frogs, the Rocky Mountain tailed frog (Ascaphus montanus) and the Coastal tailed frog (A. truei). We counted labial teeth from 240 tadpoles collected across elevation (both species) and latitudinal (A. truei) gradients, providing a natural temperature gradient. We tested the effects of developmental stage and local temperature conditions on labial tooth number. We found that labial tooth number variation was independently affected by both developmental stage and local temperature, as well as the interacting effects of these two variables (pseudo-R2 = 67-77%). Our results also uncovered consistent patterns in labial tooth row formula across the ranges of both species; however, A. truei tadpoles from northern British Columbia had a unique bifurcation of a posterior tooth row. This study highlights the diversity in intraspecific tadpole oral morphology and the interacting processes that drive it.

ecology↗

bioRxiv2019

Combining genotype, phenotype, and environmental data to delineate site-adjusted provenance strategies for ecological restoration

Despite the importance of climate-adjusted provenancing to mitigate the effects of environmental change, climatic considerations alone are insufficient when restoring highly degraded sites. Here we propose a comprehensive landscape genomic approach to assist the restoration of moderately disturbed and highly degraded sites. To illustrate it we employ genomic datasets comprising thousands of single nucleotide polymorphisms from two plant species suitable for the restoration of iron-rich Amazonian Savannas. We first use a subset of neutral loci to assess genetic structure and determine the genetic neighborhood size. We then identify genotype-phenotype-environment associations, map adaptive genetic variation, and predict adaptive genotypes for restoration sites. Whereas local provenances were found optimal to restore a moderately disturbed site, a mixture of genotypes seemed the most promising strategy to recover a highly degraded mining site. We discuss how our results can help define site-adjusted provenancing strategies, and argue that our methods can be more broadly applied to assist other restoration initiatives.

ecology↗

bioRxiv2017

Using genotype-environment associations to identify multilocus local adaptation

Identifying adaptive loci can provide insight into the mechanisms underlying local adaptation. Genotype-environment association (GEA) methods, which identify these loci based on correlations between genetic and environmental data, are particularly promising. Univariate methods have dominated GEA, despite the high dimensional nature of genotype and environment. Multivariate methods, which analyze many loci simultaneously, may be better suited to these data since they consider how sets of markers covary in response to environment. These methods may also be more effective at detecting adaptive processes that result in weak, multilocus signatures. Here, we evaluate four multivariate methods, and five univariate and differentiation-based approaches, using published simulations of multilocus selection. We found that Random Forest performed poorly for GEA. Univariate GEAs performed better, but had low detection rates for loci under weak selection. Constrained ordinations showed a superior combination of low false positive and high true positive rates across all levels of selection. These results were robust across the demographic histories, sampling designs, sample sizes, and levels of population structure tested. The value of combining detections from different methods was variable, and depended on study goals and knowledge of the drivers of selection. Reanalysis of genomic data from gray wolves highlighted the unique, covarying sets of adaptive loci that could be identified using redundancy analysis, a constrained ordination. Although additional testing is needed, this study indicates that constrained ordinations are an effective means of detecting adaptation, including signatures of weak, multilocus selection, providing a powerful tool for investigating the genetic basis of local adaptation.

genomics↗