Data from: Combinations of Spok genes create multiple meiotic drivers in Podospora
Vogan, Aaron A. ; Ament-Velásquez, S.L. ; Granger-Farbos, Alexandra ; Svedberg, Jesper ; Bastiaans, Eric ; Debets, Fons ; Coustou, Virginie ; Yvanne, Hélène ; Clavé, Corinne ; Saupe, Sven J. ; Johannesson, Hanna - \ 2019
podospora anserina - meiotic drive - genomics - gene drive - Podospora pauciseta - Spore-killing - Spok - genomic conflict
Meiotic drive is the preferential transmission of a particular allele during sexual reproduction. The phenomenon is observed as spore killing in multiple fungi. In natural populations of Podospora anserina, seven spore killer types (Psks) have been identified through classical genetic analyses. Here we show that the Spok gene-family underlies the Psks. The combination of Spok genes at different chromosomal locations defines the spore killer types and creates a killing hierarchy within the same population. We identify two novel Spok homologs located within a large (74-167 kbp) region (the Spok block) that resides in different chromosomal locations in given strains. We confirm that the SPOK protein performs both killing and resistance functions and show that these activities are dependent on distinct domains, a predicted nuclease and kinase domain. Genomic and phylogenetic analyses across ascomycetes suggest that the Spok genes disperse via cross-species transfer, and evolve by duplication and diversification within lineages.
Meiotic drive of female-inherited supernumerary chromosomes in a pathogenic fungus
Habig, Michael ; Kema, Gert Hj ; Holtgrewe Stukenbrock, Eva - \ 2018
eLife 7 (2018). - ISSN 2050-084X - 20 p.
accessory chromosome - B chromosome - chromosomes - gene expression - genetics - genomics - meiotic drive - selfish genetic elements - tetrad analysis - Zymoseptoria tritici
Meiosis is a key cellular process of sexual reproduction that includes pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungus Zymoseptoria tritici that possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired. Unpaired chromosomes inherited from the male parent as well as paired supernumerary chromosomes in general showed Mendelian inheritance. In contrast, unpaired chromosomes inherited from the female parent showed non-Mendelian inheritance but were amplified and transmitted to all meiotic products. We concluded that the supernumerary chromosomes of Z. tritici show a meiotic drive and propose an additional feedback mechanism during meiosis, which initiates amplification of unpaired female-inherited chromosomes.
High prevalence of a fungal prion
Debets, A.J.M. ; Dalstra, H.J.P. ; Slakhorst, S.M. ; Koopmanschap-Memelink, A.B. ; Hoekstra, R.F. ; Saupe, S.J. - \ 2012
Proceedings of the National Academy of Sciences of the United States of America 109 (2012)26. - ISSN 0027-8424 - p. 10432 - 10437.
podospora-anserina - vegetative incompatibility - het-s - heterokaryon incompatibility - neurospora-crassa - meiotic drive - yeast prion - mechanism - diseases - genes
Prions are infectious proteins that cause fatal diseases in mammals. Prions have also been found in fungi, but studies on their role in nature are scarce. The proposed biological function of fungal prions is debated and varies from detrimental to benign or even beneficial. [Het-s] is a prion of the fungus Podospora anserina. The het-s locus exists as two antagonistic alleles that constitute an allorecognition system: the het-s allele encoding the protein variant capable of prion formation and the het-S allele encoding a protein variant that cannot form a prion. We document here that het-s alleles, capable of prion formation, are nearly twice as frequent as het-S alleles in a natural population of 112 individuals. Then, we report a 92% prevalence of [Het-s] prion infection among the het-s isolates and find evidence of the role of the [Het-s]/het-S allorecognition system on the incidence of infection by a deleterious senescence plasmid. We explain the het-s/het-S allele ratios by the existence of two selective forces operating at different levels. We propose that during the somatic stage, the role of [Het-s]/HET-S in allorecognition leads to frequency-dependent selection for which an equilibrated frequency would be optimal. However, in the sexual cycle, the [Het-s] prion causes meiotic drive favoring the het-s allele. Our findings indicate that [Het-s] is a selected and, therefore, widespread prion whose activity as selfish genetic element is counteracted by balancing selection for allorecognition polymorphism
Rainfall-driven sex-ratio genes in African buffalo suggested by correlations between Y-chromosomal haplotype frequencies and foetal sex ratio
Hooft, W.F. van; Prins, H.H.T. ; Getz, W.M. ; Jolles, A.E. ; Wieren, S.E. van; Greyling, B.J. ; Helden, P.D. ; Bastos, A.D.S. - \ 2010
BMC Evolutionary Biology 10 (2010). - ISSN 1471-2148 - 11 p.
cattle bos-taurus - syncerus-caffer - male-fertility - meiotic drive - bovine tuberculosis - drosophila-melanogaster - microsatellite analysis - natural-populations - sperm - selection
Background - The Y-chromosomal diversity in the African buffalo (Syncerus caffer) population of Kruger National Park (KNP) is characterized by rainfall-driven haplotype frequency shifts between year cohorts. Stable Y-chromosomal polymorphism is difficult to reconcile with haplotype frequency variations without assuming frequency-dependent selection or specific interactions in the population dynamics of X- and Y-chromosomal genes, since otherwise the fittest haplotype would inevitably sweep to fixation. Stable Y-chromosomal polymorphism due one of these factors only seems possible when there are Y-chromosomal distorters of an equal sex ratio, which act by negatively affecting X-gametes, or Y-chromosomal suppressors of a female-biased sex ratio. These sex-ratio (SR) genes modify (suppress) gamete transmission in their own favour at a fitness cost, allowing for stable polymorphism. Results - Here we show temporal correlations between Y-chromosomal haplotype frequencies and foetal sex ratios in the KNP buffalo population, suggesting SR genes. Frequencies varied by a factor of five; too high to be alternatively explained by Y-chromosomal effects on pregnancy loss. Sex ratios were male-biased during wet and female-biased during dry periods (male proportion: 0.47-0.53), seasonally and annually. Both wet and dry periods were associated with a specific haplotype indicating a SR distorter and SR suppressor, respectively. Conclusions - The distinctive properties suggested for explaining Y-chromosomal polymorphism in African buffalo may not be restricted to this species alone. SR genes may play a broader and largely overlooked role in mammalian sex-ratio variation
Doorbreking van kruisingsbarrières tussen Oriental- en Aziatische hybriden t.b.v. van introgressie van virus, Fusarium en Botrytisresistentie
Tuyl, J.M. van - \ 2006
Wageningen : Plant Research International - 36
siergewassen - bloembollen - lelies - veredelen - commerciële hybriden - diploïdie - mitotische recombinatie - meiotic drive - ziekteresistentie - gewasbescherming - leliemozaïekvirus - fusarium - botrytis - ornamental crops - ornamental bulbs - lilies - breeding - commercial hybrids - diploidy - mitotic recombination - meiotic drive - disease resistance - plant protection - lily mottle virus - fusarium - botrytis
Dit project heeft als doel om de laatste hindernissen in het gebruik van OA-hybriden voor de lelieveredeling weg te nemen. Dit betekent: Herstel van fertiliteit d.m.v. (geïnduceerde) mitotische en meiotische polyploïdisatie (chromosoomverdubbeling). Selectie van het meest fertiele materiaal en analyse van nakomelingschappen met streven naar maximale introgressie van de diverse genomen. Onderzoek gericht op een combinatie van ziekteresistenties (Lily Mottle Virus, Fusarium en Botrytis).
Genomic conflicts in Podospora anserina = Genomische conflicten in Podospora anserina
Gaag, M. van der - \ 2005
Wageningen University. Promotor(en): Rolf Hoekstra, co-promotor(en): Fons Debets. - s.l. : S.n. - ISBN 9789085042556 - 152
pezizomycotina - schimmels - genomen - genetica - plasmiden - meiotic drive - meiose - uitkruisen - pezizomycotina - fungi - genomes - genetics - plasmids - meiotic drive - meiosis - outcrossing
This thesis deals with genomic conflicts raised by selfish elements in the ascomycete fungus Podospora anserina .Genomic conflicts arise when the effects of the selfish elements are opposite to the interests of the other parts of the genome. Two types of selfish elements are studied as well as certain characteristics of Podospora involved in the population dynamics of these elements, such as vegetative and sexual incompatibility, senescence and outcrossing.The natural habitat of Podospora anserina is dung of herbivores where it has an optimum growth temperature of 27 °C. The fungus can only reproduce sexually and the ascospores are the products of meiosis as well as the next generation of the fungus. Perithecia or fruiting bodies contain asci with four linearly arranged ascospores, which provide unique opportunities to analyse abnormal segregation and makes this fungus one of the genetic model organisms. Most ascospores are capable of completing the lifecycle of the fungus, as they contain two nuclei, each with one of the two mating types. This fungal trait is called pseudo or secondairy homothallism, and it allows sexual offspring to be produced by either selfing or outcrossing. Sometimes smaller single mating type ascospores are formed containing one nucleus and less cytoplasmic content and mitochondria. Colonies from these spores must outcross with another isolate to produce offspring. The fungal isolates used in this thesis were sampled from dung around Wageningen, the
Nonmendelian inheritance of the HET-s prion or HET-s prion domains determines the het-S spore killing system in Podospora anserina
Dalstra, H.J.P. ; Zee, R.I. van der; Swart, K. ; Hoekstra, R.F. ; Saupe, S.J. ; Debets, A.J.M. - \ 2005
Fungal Genetics and Biology 42 (2005)10. - ISSN 1087-1845 - p. 836 - 847.
meiotic drive - heterokaryon incompatibility - vegetative incompatibility - in-vivo - protein - neurospora - fungi - organization - analog - genes
Two alleles of the het-s/S locus occur naturally in the filamentous fungus Podospora anserina, het-s and het-S. The het-s encoded protein can form a prion that propagates a self-perpetuating amyloid aggregate, resulting in two phenotypes for the het-s strains. The prion-infected [Het-s] shows an antagonistic interaction to het-S whereas the prion-free [Het-s*] is neutral in interaction to het-S. The antagonism between [Het-s] and het-S is seen as heterokaryon incompatibility at the somatic level and as het-S spore killing in the sexual cycle. Two different domains of the HET-s and HET-S proteins have been identified, and a structure-function relationship has been established for interactions at the somatic level. In this study, we correlate accumulation of the HET-s and HET-S proteins (visualized using GFP) during the sexual cycle with timing of het-S spore abortion. Also, we present the structure-function relationship of the HET-s domains for interactions in the sexual cycle. We show that the constructs that ensure het-s incompatibility function in somatic mycelium are also active in het-S spore killing in the sexual cycle. In addition, paternal prion transmission and het-S spore killing has been found with the HET-s(157-289) truncated protein. The consequences of the unique transition from a coenocytic to a cellular state in the sexual phase and the timing, and localization of paternal and maternal HET-s and HET-S expression that are pertinent to prion transmission, and het-S spore killing are elaborated. These data further support our previously proposed model for het-S spore killing.