Host range expansion of asexual parasite can be explained by loss of adaptions in Muller&#39;s Ratchet

Tichkule, S; van Oosterhout, C; Cacci&#242;, SM; Weisz, F; Balan, B; Noh&#253;nkov&#225;, E; Naung, M; Ansell, BRE; Emery-Corbin, SJ; Baker, L; Lalle, M; Sv&#228;rd, S; Gasser, RB; Jex, AR

Host range expansion of asexual parasite can be explained by loss of adaptions in Muller's Ratchet

Author(s): Tichkule, S; van Oosterhout, C; Cacciò, SM; Weisz, F; Balan, B; Nohýnková, E; Naung, M; Ansell, BRE; Emery-Corbin, SJ; Baker, L; Lalle, M; Svärd, S; Gasser, RB; Jex, AR;
Details: Publication Year 2025-12-01,Volume 16,Issue #1,Page 10805
Journal Title: Nature Communications
Abstract: Sexual recombination is a hallmark of eukaryotic evolution. Without recombination, asexual eukaryotes should succumb to deleterious mutations and more rapidly evolving pathogens. Giardia duodenalis, a parasitic protist, sits within one of the earliest-branching eukaryotic lineages and has no known sexual stage. Whether Giardia are 'ancient asexuals' has been long explored but is unresolved. Here, we find clear evidence of sex in Giardia and also discover an asexual sublineage that has a broader host range than its sexual ancestor. This asexual lineage is not ancient, and is accumulating deleterious mutations. Unlike its sexual counterparts, its genetic variation lacks the signatures of selection and Red Queen coevolution. We propose a new hypothesis that explains how a mutational meltdown during Muller's Ratchet might enable asexual pathogens to expand their host ranges transiently. Fittingly, our results suggest that Giardia is not the last exception to, but rather further evidence of, the essentiality of eukaryotic sex.
Publisher: Springer Nature
Keywords: *Reproduction, Asexual/genetics; *Host Specificity/genetics; *Giardia lamblia/genetics/physiology; Animals; Phylogeny; Biological Evolution; Mutation; Genetic Variation; Parasites/genetics
Research Division(s): Infection and Global Health; Genetics and Gene Regulation; Advanced Technology and Biology
PubMed ID: 41326367
Publisher's Version: https://doi.org/10.1038/s41467-025-65843-4
Open Access at Publisher's Site: https://doi.org/10.1038/s41467-025-65843-4
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2025-12-05 09:30:40

Last Modified: 2025-12-05 09:30:58