My group and I study the mechanisms (e.g., selection, migration) that influence the maintenance of genetic diversity in asexual-sexual species complexes, using the freshwater cladoceran genus, Daphnia, as our primary model organism. My research bridges the fields of population genetics, environmental genomics, and evolutionary ecology. In my lab, a variety of molecular techniques (e.g., microsatellites, DNA sequencing, and Next-Gen genomics) are used to examine the population genetic/genomic structure of aquatic organisms, with most of my work focusing on zooplankton. Study systems have ranged from small Arctic rock pools/tundra ponds to large glacial lakes in Europe and North America (including the Laurentian Great Lakes). We use a combination of field surveys and laboratory experiments to examine population genetic x environment interactions.
Over the past several decades, in collaboration with colleagues in Europe and the U.S., we have been focusing on the ecological and genetic information held in lake/pond sediment egg banks of freshwater invertebrates, primarily Daphnia. We have been in the vanguard that has developed the field of “resurrection ecology” (i.e., hatching of dormant propagules such as seeds, cysts, or Daphnia resting eggs in pond/lake sediments). We utilize a variety of techniques that span the fields of paleolimnology, molecular genetics, ecology (i.e., direct hatching of eggs, selection experiments), and environmental genomics (i.e., Next-Gen sequencing). Together, these methods allow us to examine long-term (i.e., decadal, centennial) shifts in population genetic/genomic structure that may be associated with concomitant shifts in environmental factors (e.g., nutrient/eutrophication history, freshwater salinization due to road salt run-off, climate change). We aim to look at how shifts in environmental factors may influence long-term temporal genetic heterogeneity in natural populations and how these populations may (or may not) be adapting/evolving in the face of increasing environmental challenges in the Anthropocene.
Wersebe, M.J. and L.J. Weider. 2023. Resurrection genomics provides molecular and phenotypic evidence of rapid adaptation to salinization in a keystone aquatic species. Proceedings of the National Academy of Sciences (PNAS) https://doi.org/10.1073/pnas.2217276120
Frisch, D., P.K. Morton, P. Roy Chowdhury, B. Culver, J.K. Colbourne, L.J. Weider, and P.D. Jeyasingh. 2014. A millennial-scale chronicle of evolutionary responses to cultural eutrophication in Daphnia. Ecology Letters 17:360-368. https://doi.org/10.1111/ele.12237
Weider, L.J., J.J. Elser, T.J. Crease, M. Mateos, J. Cotner, and T. Markow. 2005. The functional significance of ribosomal(r)DNA variation: Impacts on the evolutionary ecology of organisms. Annual Review Ecology Evolution Systematics 36:219-242. https://doi.org/10.1146/annurev.ecolsys.36.102003.152620
Weider, L. J., W. Lampert, M. Wessels, J. K. Colbourne and P. Limburg. 1997. Long-term genetic shifts in microcrustacean egg bank associated with anthropogenic changes in Lake Constance ecosystem. Proc. R. Soc. Lond. Series B. 264:1613-1618. https://www.jstor.org/stable/50770
De Meester, L., L.J. Weider, and R. Tollrian. 1995. Alternative anti-predator defenses and genetic polymorphism in a pelagic predator-prey system. Nature 378:483-485. https://www.nature.com/articles/378483a0
