Biology subjects

Weider, L. J.

Publications and source records attributed to Weider, L. J..

2 recordsLinked to original sources

bioRxiv2024

A tale of two lakes: divergent evolutionary trajectories of two Daphnia populations experiencing distinct environments

Most studies of local adaptation substitute the correlation between spatial distance and environmental heterogeneity for the temporal dynamics over which local adaptation evolves. The availability of detailed ecological and genomic information from lake sediments provides an opportunity to study local adaptation with unparalleled clarity from the temporal perspective. Inference can be further enhanced by including multiple lakes along ecological axes to further isolate the effects of ecological change in driving local adaptation. Lakes throughout the world face the impact of numerous anthropogenically induced environmental changes. Top among these is the eutrophication of freshwaters from agriculture, development and land-use change. Here we use the genetic information recorded in lake sediments of two lakes experiencing contrasting histories of land-use change to study the evolution of local adaptation in the lakes Daphnia pulicaria populations. Utilizing nextRAD derived Single Nucleotide Polymorphisms (SNPs), we studied the evolutionary trajectories of Daphnia pulicaria in both lakes. Using gene-environment correlations and Fst tests for selection we found SNPs that appear to be under selection in both lakes. Specifically, we found more outlier SNPs in the highly impacted lake using Fst-based tests for selection. Conversely, gene-environment tests revealed the reverse pattern. We discuss numerous facets of experimental design that must be considered when using resurrection ecology to study local adaptation and critically evaluate how they may have impacted the results of this investigation. Lay SummaryResurrection ecology, the resuscitation or hatching of decades or centuries old dormant eggs, seeds or cysts provides the opportunity to study evolution in action. Here, we use resurrection ecology paired with Single Nucleotide Polymorphism (SNP) genotyping to study the evolutionary responses of two populations of Daphnia pulicaria to contrasting changes in the nutrient dynamics of their respective lakes. In the lake with more drastic changes in nutrient pollution, we find a stronger shift in allele frequencies through time and at a larger number of affected genomic positions compared with the environmentally more stable lake. However, Bayesian gene-environment correlations were stronger in the more stable lake reflecting higher power to detect correlations among allele frequency change and paleo-environmental variables in this location. Our results suggest that numerous factors might impact the ability to use different methodologies to detect local adaptation over time using resurrection ecology.

evolutionary biology↗

bioRxiv2022

Resurrection genomics provides molecular and phenotypic evidence of rapid adaptation to salinization in a keystone aquatic species

Ecologists and evolutionary biologists are increasingly cognizant of rapid adaptation in wild populations. Rapid adaptation to anthropogenic environmental change is critical for maintaining biodiversity and ecosystems services into the future. Anthropogenic salinization of freshwater ecosystems is quickly emerging as a primary threat, which is well documented in the northern temperate ecoregion. Specifically, many northern temperate lakes have undergone extensive salinization because of urbanization and the associated increase in impervious surfaces causing runoff, and the extensive use of road deicing salts (e.g., NaCl). It remains unclear if increasing salinization will lead to extirpation of species from these systems. Using a "resurrection genomics" approach, we investigated whether the keystone aquatic herbivore, Daphnia pulicaria, has evolved increased salinity tolerance in a severely salinized lake located in Minnesota, USA. Whole genome resequencing of 54 Daphnia clones from the lake and hatched from resting eggs that represent a 25-year temporal contrast demonstrates that many regions of the genome containing genes related to osmoregulation are under selection in the study population. Tolerance assays of clones revealed that the most recent clones are more tolerant to salinity than older clones; this pattern is concomitant with the temporal pattern of stabilizing salinity in this lake. Together, our results demonstrate that keystone species such as Daphnia can rapidly adapt to increasing freshwater salinization. Further, our results indicate that rapid adaptation to salinity may allow lake Daphnia populations to persist in the face of anthropogenic salinization maintaining the food webs and ecosystem services they support despite global environmental change. Significance StatementRapid adaptation to human-induced environmental change is critical for preserving biodiversity and ecosystem services into the future. A key question is whether populations of keystone species can rapidly adapt to maintain the ecosystems they support. We investigated rapid adaptation to anthropogenic salinization in Daphnia pulicaria, a keystone aquatic herbivore in lake ecosystems. By resuscitating decades-old resting eggs, we investigate genomic changes across an approximately 25-year temporal contrast from a severely salinized lake. We report that the genes showing signatures of natural selection throughout the genome are related to osmoregulation and ion regulation. Phenotyping clones for salinity tolerance revealed evidence that genetic changes may underlie rapid evolution. We provide molecular genomic and phenotypic evidence for rapid adaptation to salinity in D. pulicaria.

evolutionary biology↗