@article{21900,
  abstract     = {Individually silencing 125 fruit fly genes reveals opposing fitness effects of mutations between females and males, as well as between germline and somatic tissues.},
  author       = {Ruzicka, Filip},
  issn         = {2397-334X},
  journal      = {Nature Ecology & Evolution},
  publisher    = {Springer Nature},
  title        = {{Reverse genetics of sexual antagonism}},
  doi          = {10.1038/s41559-026-03036-y},
  year         = {2026},
}

@article{20044,
  abstract     = {Genetic trade-offs—which occur when variants that are beneficial in some contexts of natural selection are harmful in others—can influence a wide range of evolutionary phenomena, from the maintenance of genetic variation to the evolution of aging and sex differences. An extensive body of evolutionary theory has focused on the consequences of such trade-offs, and recent analyses of Fisher’s geometric model have further quantified the expected proportion of new mutations that exhibit trade-offs. However, the theory remains silent regarding the prevalence of trade-offs among the variants that contribute to adaptation. Here, we extend Fisher’s geometric model to predict the prevalence of trade-offs among the adaptive mutations that become established or fixed in a population. We consider trade-offs between sexes, habitats, fitness components, and temporally fluctuating environments. In all 4 scenarios, trade-off alleles are consistently under-represented among established relative to new beneficial mutations—an effect that arises from the greater susceptibility of trade-off alleles to genetic drift. Adaptation during a population size decline exacerbates this deficit of trade-offs among established mutations, whereas population expansions dampen it. Consequently, threatened populations should primarily adapt using unconditionally beneficial alleles, while invasive populations are more prone to adaptation using variants that exhibit trade-offs.},
  author       = {Connallon, Tim and Czuppon, Peter and Olito, Colin and Goedert, Debora and Kokko, Hanna and Nava-Bolaños, Angela and Nilén, Sofie and Svensson, Erik I and Zwoinska, Martyna and Dutoit, Ludovic and Ruzicka, Filip},
  issn         = {1558-5646},
  journal      = {Evolution},
  number       = {7},
  pages        = {1243--1255},
  publisher    = {Oxford University Press},
  title        = {{Predicting the prevalence of genetic trade-offs among adaptive substitutions}},
  doi          = {10.1093/evolut/qpaf061},
  volume       = {79},
  year         = {2025},
}

@article{20655,
  abstract     = {Traits that affect organismal fitness are often highly 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 in which natural selection maintains genetic variation – is a century‐old explanation to resolve this puzzle that has gained recent momentum from genome‐scale methods for detecting it. Yet evaluating whether balancing selection can, in fact, resolve the puzzle 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 – non‐random mating between individuals, ploidy levels, genetic drift, linkage, and 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.},
  author       = {Ruzicka, Filip and Zwoinska, Martyna K. and Goedert, Debora and Kokko, Hanna and Li Richter, Xiang‐Yi and Moodie, Iain R. and Nilén, Sofie and Olito, Colin and Svensson, Erik I. and Czuppon, Peter and Connallon, Tim},
  issn         = {1469-185X},
  journal      = {Biological Reviews},
  publisher    = {Wiley},
  title        = {{A century of theories of balancing selection}},
  doi          = {10.1111/brv.70103},
  year         = {2025},
}

@article{18479,
  abstract     = {The dominance of beneficial mutations is a key evolutionary parameter affecting the rate and genetic basis of adaptation, yet it is notoriously difficult to estimate. A leading method to infer it is to compare the relative rates of adaptive substitution for X-linked and autosomal genes, which—according to a classic model by Charlesworth et al. (1987)—is a simple function of the dominance of new beneficial mutations. Recent evidence that rates of adaptive substitution are faster for X-linked genes implies, accordingly, that beneficial mutations are usually recessive. However, this conclusion is incompatible with leading theories of dominance, which predict that beneficial mutations tend to be dominant or overdominant with respect to fitness. To address this incompatibility, we use Fisher’s geometric model to predict the distribution of fitness effects of new mutations and the relative rates of positively selected substitution on the X and autosomes. Previous predictions of faster-X theory emerge as a special case of our model in which the phenotypic effects of mutations are small relative to the distance to the phenotypic optimum. But as mutational effects become large relative to the optimum, we observe an elevated tempo of positively selected substitutions on the X relative to the autosomes across a broader range of dominance conditions, including those predicted by theories of dominance. Our results imply that, contrary to previous models, dominant and overdominant beneficial mutations can plausibly generate patterns of faster-X adaptation. We discuss resulting implications for genomic studies of adaptation and inferences of dominance.},
  author       = {Mcdonough, Yasmine and Ruzicka, Filip and Connallon, Tim},
  issn         = {1091-6490},
  journal      = {Proceedings of the National Academy of Sciences of the United States of America},
  number       = {44},
  publisher    = {National Academy of Sciences},
  title        = {{Reconciling theories of dominance with the relative rates of adaptive substitution on sex chromosomes and autosomes}},
  doi          = {10.1073/pnas.2406335121},
  volume       = {121},
  year         = {2024},
}