Biology subjects

Zwoinska, M. K.

Publications and source records attributed to Zwoinska, M. K..

4 recordsLinked to original sources

bioRxiv2026

Transgenerational inheritance is variable across Caenorhabditis worms

Transgenerational epigenetic inheritance (TEI) allows organisms to express heritable responses to environmental stresses, and can potentially contribute to adaptive evolution. The microbivorous model organism Caenorhabditis elegans is perhaps the best example, as it can learn to avoid pathogenic Pseudomonas bacteria and transmit this learned avoidance to its offspring. However, the extent to which TEI is widespread in nature remains unclear, and therefore our understanding of the generality of this response is limited. To address this, we conducted the first comparative study of TEI across five Caenorhabditis nematode worm species (C. kamaaina, C. elegans, C. tropicalis, C. remanei and C. briggsae). These species differ in RNA interference competence and in the degree of sequence homology between Caenorhabditis worm genes and bacterial RNAs, two factors thought to influence epigenetic responses. We examined transgenerational avoidance of P. vranovensis, a pathogen that reduces fitness in all five species tested. In addition to C. elegans, we found that C. remanei also exhibited transgenerational avoidance of P. vranovensis, whereas neither learning nor inheritance was observed in the other three species. In addition, parental exposure to P. vranovensis also conferred a transgenerational survival benefit upon pathogen encounter in C. elegans, C. remanei and C. tropicalis. Our findings show that TEI of pathogen avoidance extends beyond C. elegans but is not a general response across Caenorhabditis species. This shows that TEI is a species-specific response and highlights the need to understand TEI alongside other responses to environmental variability.

evolutionary biology↗

bioRxiv2026

From constraint to opportunity: Relaxing sexual antagonism reveals adaptive potential maintained by balancing selection

Despite ongoing selection, genetic variation in fitness-related traits often persists. Balancing selection can maintain polymorphisms through genetic trade-offs, including those between the sexes. Sexually antagonistic (SA) selection is challenging to detect at the genomic level and its broader evolutionary importance, especially for complex traits, remains unclear. To investigate this, we conducted an evolve-and-resequence experiment in Callosobruchus maculatus, manipulating the strength of SA trade-offs over body size and tracking genome-wide responses. When selection simultaneously favored larger females and smaller males, allele frequency changes were constrained and genome-wide divergence remained limited. In contrast, relaxing SA trade-offs by selecting on only one sex led to large, repeatable allele frequency shifts. These loci also showed signatures of long-term balancing selection in the ancestral population. Together, our results demonstrate that SA trade-offs can act both as a constraint, limiting sex-specific responses under antagonistic selection pressures, but also as a source of adaptive potential once antagonism is relaxed.

evolutionary biology↗

bioRxiv2025

A century of theories of balancing selection

Traits that affect organismal fitness are often very genetically variable. This genetic variation is vital for populations to adapt to their environments, but it is also surprising given that nature (after all) "selects" the best genotypes at the expense of those that fall short. Explaining the extensive genetic variation of fitness-related traits is thus a longstanding puzzle in evolutionary biology, with cascading implications for ecology, conservation, and human health. Balancing selection--an umbrella term for scenarios of natural selection that maintain genetic variation-- is a century-old explanation to resolve this paradox that has gained recent momentum from genome-scale methods for detecting it. Yet evaluating whether balancing selection can, in fact, resolve the paradox is challenging, given the logistical constraints of distinguishing balancing selection from alternative hypotheses and the daunting collection of theoretical models that formally underpin this debate. Here, we track the development of balancing selection theory over the last century and provide an accessible review of this rich collection of models. We first outline the range of biological scenarios that can generate balancing selection. We then examine how fundamental features of genetic systems--including non-random mating between individuals, differences in ploidy, genetic drift, and different genetic architectures of traits-- have been progressively incorporated into the theory. We end by linking these theoretical predictions to ongoing empirical efforts to understand the evolutionary processes that explain genetic variation.

evolutionary biology↗

bioRxiv2019

Environmental variation mediates the evolution of anticipatory parental effects

Theory maintains that when future environment is predictable, parents should adjust the phenotype of their offspring to match the anticipated environment. The plausibility of positive anticipatory parental effects is hotly debated and the experimental evidence for the evolution of such effects is currently lacking. We experimentally investigated the evolution of anticipatory maternal effects in a range of environments that differ drastically in how predictable they are. Populations of the nematode Caenorhabditis remanei, adapted to 20{degrees}C, were exposed to a novel temperature (25{degrees}C) for 30 generations with either positive or zero correlation between parent and offspring environment. We found that populations evolving in novel environments that were predictable across generations evolved a positive anticipatory maternal effect, since they required maternal exposure to 25{degrees}C to achieve maximum reproduction in that temperature. In contrast, populations evolving under zero environmental correlation had lost this anticipatory maternal effect. Similar but weaker patterns were found if instead rate-sensitive population growth was used as a fitness measure. These findings demonstrate that anticipatory parental effects evolve in response to environmental change so that ill-fitting parental effects can be rapidly lost. Evolution of positive anticipatory parental effects can aid population viability in rapidly changing but predictable environments. Impact summaryParents can help their offspring by adjusting offsprings phenotype to match their environment. Such anticipatory parental effects would be beneficial, but only if parents can accurately predict the environment in which their offspring will develop and live. The plausibility of such anticipatory parental effects is hotly debated. The theory is clear that the predictability of the environment should play a defining role. We used an "experimental evolution" approach in a fast reproducing nematode worm Caenorhabditis remanei to tackle this question and follow the evolution of parental effects in different environments in real-time. We found that populations evolving in a novel but predictable environment indeed had anticipatory parental effects that increased fitness of their offspring in that environment. In contrast, when evolving in an unpredictable environment where such parental effects would be disadvantageous, the parental effect was rapidly lost in evolution. Our novel experimental environments were constructed by exposing worms to increased temperature. Anticipatory parental effects play an important role in adaptation to novel environments and will affect the viability of populations under climate heating.

evolutionary biology↗