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Your search keyword '"Przesmycka, Karolina"' showing total 11 results
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11 results on '"Przesmycka, Karolina"'

7. Molecular Ecology / Expansion of frozen hybrids in the guppy ectoparasite, Gyrodactylus turnbulli

Author

Konczal, Mateusz, Przesmycka, Karolina J., Mohammed, Ryan S., Hahn, Christoph, Cable, Jo, and Radwan, Jacek

Subjects
heterosis, Gyrodactylus, clonal reproduction, invasion, hybridization
Abstract

Hybridization is one of the major factors contributing to the emergence of highly successful parasites. Hybrid vigour can play an important role in this process, but subsequent rounds of recombination in the hybrid population may dilute its effects. Increased fitness of hybrids can, however, be frozen by asexual reproduction. Here, we identify invasion of a ‘frozen hybrid genotype in natural populations of Gyrodactylus turnbulli, a facultatively sexual ectoparasitic flatworm that causes significant damage to its fish host. We resequenced genomes of these parasites infecting guppies from six Trinidad and Tobago populations, and found surprisingly high discrepancy in genomewide nucleotide diversity between islands. The elevated heterozygosity on Tobago is maintained by predominantly clonal reproduction of hybrids formed from two diverged genomes. Hybridization has been followed by spread of the hybrids across the island, implying a selective advantage compared with native genotypes. Our results thus highlight that a single outcrossing event may be independently sufficient to cause pathogen expansion. (VLID)5769836 Version of record

Published
2021

11. Immunogenetic novelty confers a selective advantage in host-pathogen coevolution.

Author

Raubic, Jarosław, Przesmycka, Karolina J., Radwan, Jacek, Phillips, Karl P., Cable, Joanne, Mohammed, Ryan S., Herdegen-Radwan, Magdalena, and van Oosterhout, Cock

Subjects
*IMMUNOGENETICS, *MAJOR histocompatibility complex, *PATHOGENIC microorganisms, *GUPPIES, *GENETIC polymorphisms
Abstract

The major histocompatibility complex (MHC) is crucial to the adaptive immune response of vertebrates and is among the most polymorphic gene families known. Its high diversity is usually attributed to selection imposed by fast-evolving pathogens. Pathogens are thought to evolve to escape recognition by common immune alleles and hence, novel MHC alleles, introduced through mutation, recombination, or gene flow, are predicted to give hosts superior resistance. Although this theoretical prediction underpins host-pathogen "Red Queen" coevolution, it has not been demonstrated in the context of natural MHC diversity. Here, we experimentally tested whether novel MHC variants (both alleles and functional "supertypes") increased resistance of guppies (Poecilia reticulata) to a common ectoparasite (Gyrodactylus turnbulli). We used exposure-controlled infection trials with wild-sourced parasites, and Gyrodactylus-naïve host fish that were F2 descendants of crossed wild populations. Hosts carrying MHC variants (alleles or supertypes) that were new to a given parasite population experienced a 35-37% reduction in infection intensity, but the number of MHC variants carried by an individual, analogous to heterozygosity in single-locus systems, was not a significant predictor. Our results provide direct evidence of novel MHC variant advantage, confirming a fundamental mechanism underpinning the exceptional polymorphism of this gene family and highlighting the role of immunogenetic novelty in host-pathogen coevolution. [ABSTRACT FROM AUTHOR]

Published
2018
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