Anastasia Lyulina

All Publications

• Dominance reversal maintains large-effect resistance polymorphism in temporally varying environments. bioRxiv : the preprint server for biology Karageorgi, M., Lyulina, A. S., Bitter, M. C., Lappo, E., Greenblum, S. I., Mouza, Z. K., Tran, C. T., Huynh, A. V., Oken, H., Schmidt, P., Petrov, D. A. 2025

  Abstract

  A central challenge in evolutionary biology is to uncover mechanisms maintaining functional genetic variation1. Theory suggests that dominance reversal, whereby alleles subject to fluctuating selection are dominant when beneficial and recessive when deleterious, can help stabilize large-effect functional variation in temporally varying environments2,3. However, empirical evidence for dominance reversal is scarce because testing requires both knowing the genetic architecture of relevant traits and measuring the dominance effects on fitness in natural conditions4. Here, we show that large-effect, insecticide-resistance alleles at the Ace locus in Drosophila melanogaster5,6 persist worldwide at intermediate frequencies and exhibit dominance reversal in fitness as a function of the presence of an organophosphate insecticide. Specifically, we use laboratory assays to show that the resistance benefits driven by these alleles are dominant, while the associated costs are recessive (or codominant). Further, by tracking insecticide resistance and genome-wide allele frequencies in field mesocosms, we find that resistance and resistant alleles increase and then decrease rapidly in response to an insecticide pulse but are maintained at low frequencies in the absence of pesticides. We argue that this pattern is only consistent with beneficial reversal of dominance. We use Wright's theory of dominance7 to hypothesize that dominance reversal should be common in general if the environmental shifts that make alleles deleterious also make them behave effectively as loss-of-function and thus recessive alleles . We also use the known haplotype structure of mesocosm populations to establish that the insecticide pulse generates chromosome-scale genomic perturbations of allele frequencies at linked sites. Overall, our results provide compelling evidence that this mechanism can maintain functional genetic variation and enable rapid adaptation to environmental shifts that can impact patterns of genomic variation at genome-wide scales via linked fluctuating selection.

  View details for DOI 10.1101/2024.10.23.619953

  View details for PubMedID 39554016

• Linkage equilibrium between rare mutations. Genetics Lyulina, A. S., Liu, Z., Good, B. H. 2024

  Abstract

  Recombination breaks down genetic linkage by reshuffling existing variants onto new genetic backgrounds. These dynamics are traditionally quantified by examining the correlations between alleles, and how they decay as a function of the recombination rate. However, the magnitudes of these correlations are strongly influenced by other evolutionary forces like natural selection and genetic drift, making it difficult to tease out the effects of recombination. Here we introduce a theoretical framework for analyzing an alternative family of statistics that measure the homoplasy produced by recombination. We derive analytical expressions that predict how these statistics depend on the rates of recombination and recurrent mutation, the strength of negative selection and genetic drift, and the present-day frequencies of the mutant alleles. We find that the degree of homoplasy can strongly depend on this frequency scale, which reflects the underlying timescales over which these mutations occurred. We show how these scaling properties can be used to isolate the effects of recombination, and discuss their implications for the rates of horizontal gene transfer in bacteria.

  View details for DOI 10.1093/genetics/iyae145

  View details for PubMedID 39222343

• Electroporation of asymmetric phospholipid membranes. The Journal of Physical Chemistry B Gurtovenko, A. A., Lyulina, A. S. 2014; 118 (33): 9909–9918

  View details for DOI 10.1021/jp5028355