Recombining your way out of trouble: the genetic architecture of hybrid fitness under environmental stress

Hybridization between species is a fundamental evolutionary force that can both promote and delay adaptation. There is a deficit in our understanding of the genetic basis of hybrid fitness, especially in non-domesticated organisms. We also know little about how hybrid fitness changes as a function of environmental stress. Here, we made genetically variable F2 hybrid populations from two divergent Saccharomyces yeast species, exposed populations to ten toxins, and sequenced the most resilient hybrids on low coverage using ddRADseq. We expected to find strong negative epistasis and heterozygote advantage in the hybrid genomes. We investigated three aspects of hybridness: 1) hybridity, 2) interspecific heterozygosity, and 3) epistasis (positive or negative associations between non-homologous chromosomes). Linear mixed effect models revealed strong genotype-by-environment interactions with many chromosomes and chromosomal interactions showing species-biased content depending on the environment. Against our predictions, we found extensive selection against heterozygosity such that homozygous allelic combinations from the same species were strongly overrepresented in an otherwise hybrid genomic background. We also observed multiple cases of positive epistasis between chromosomes from opposite species, confirmed by epistasis- and selection-free simulations, which is surprising given the large divergence of the parental species (~15% genome-wide). Together, these results suggest that stress-resilient hybrid genomes can be assembled from the best features of both parents, without paying high costs of negative epistasis across large evolutionary distances. Our findings illustrate the importance of measuring genetic trait architecture in an environmental context when determining the evolutionary potential of hybrid populations

Asynchronous spore germination in isogenic natural isolates of Saccharomyces paradoxus

Spores from wild yeast isolates often show great variation in the size of colonies they produce, for largely unknown reasons. Here we measure the colonies produced from single spores from six different wild Saccharomyces paradoxus strains. We found remarkable variation in spore colony sizes, even among spores that were genetically identical. Different strains had different amounts of variation in spore colony sizes, and variation was not affected by the number of preceding meioses, or by spore maturation time. We used time-lapse photography to show that wild strains also have high variation in spore germination timing, providing a likely mechanism for the variation in spore colony sizes. When some spores from a laboratory strain make small colonies, or no colonies, it usually indicates a genetic or meiotic fault. Here, we demonstrate that in wild strains spore colony size variation is normal. We discuss and assess potential adaptive and non-adaptive explanations for this variation

Measuring microbial fitness in a field reciprocal transplant experiment

Microbial fitness is easy to measure in the laboratory, but difficult to measure in the field. Laboratory fitness assays make use of controlled conditions and genetically modified organisms, neither of which are available in the field. Among other applications, fitness assays can help researchers detect adaptation to different habitats or locations. We designed a competitive fitness assay to detect adaptation of Saccharomyces paradoxus isolates to the habitat they were isolated from (oak or larch leaf litter). The assay accurately measures relative fitness by tracking genotype frequency changes in the field using digital droplet PCR (DDPCR). We expected locally adapted S. paradoxus strains to increase in frequency over time when growing on the leaf litter type from which they were isolated. The DDPCR assay successfully detected fitness differences among S. paradoxus strains, but did not find a tendency for strains to be adapted to the habitat they were isolated from. Instead, we found that the natural alleles of the hexose transport gene we used to distinguish S. paradoxus strains had significant effects on fitness. The origin of a strain also affected its fitness: strains isolated from oak litter were generally fitter than strains from larch litter. Our results suggest that dispersal limitation and genetic drift shape S. paradoxus populations in the forest more than local selection does, although further research is needed to confirm this. Tracking genotype frequency changes using DDPCR is a practical and accurate microbial fitness assay for natural environments

EUROPOS TARYBOS KURIAMA PRIDĖTINĖ VERTĖ ADMINISTRACINEI TEISEI: BENDRŲ EUROPINIŲ GERO ADMINISTRAVIMO NUOSTATŲ VYSTYMAS IR JŲ REIKŠMĖ EUROPOS TARYBOS VALSTYBIŲ NARIŲ NACIONALINEI TEISEI

Although the Council of Europe has been working in the area of administrative law for decades, the body of pan-European general principles of good administration developed by this organisation remains mostly uncharted. This article attempts to help fill this academic gap by examining the scope and content of the pan-European principles of administrative law stemming from the Council of Europe, with a special emphasis on the principle of good administration. In doing so, the sources of administrative law of the Council of Europe are considered, together with the mechanisms by which they penetrate and permeate domestic legal systems. This article concludes that the work done by the Council of Europe in the administrative field has contributed to a process of harmonisation in its Member States’ domestic law, but that the exact scope thereof has yet to be uncovered and requires further research.Nepaisant to, kad Europos Taryba administracinės teisės plotmėje veikia ne vieną dešimtmetį, šios organizacijos išplėtotos bendros europinės gero administravimo nuostatos tebėra nepakankamai ištirtos. Šiuo straipsniu siekiama iš dalies užpildyti šią akademinę spragą bei įvertinti Europos Tarybos plėtojamų bendrų europinių administracinės teisės principų apimtį ir turinį, ypatingą dėmesį skiriant organizacijos skleidžiamam gero administravimo imperatyvui. Siekiant šio tikslo, straipsnyje apžvelgiami iš Europos Tarybos kylančios administracinės teisės šaltiniai ir būdai, leidžiantys šiai teisei prasiskverbti į organizacijos valstybių narių nacionalines teisės sistemas. Straipsnis baigiamas išvada, kad Europos Tarybos veikla administracinės teisės plotmėje prisideda prie jos valstybių narių nacionalinių teisinių sistemų glaudėjimo, tačiau tikslus šios organizacijos daromas poveikis turi būti įvertintas nuodugnesnių tyrimų

Remedies Against Administrative Silence in the Netherlands

This chapter introduces the remedies against silence of the administration in the Netherlands and provides data on the functioning of these remedies in practice. Single-case decisions requested by an interested party shall be taken within the time limit prescribed by statutory regulation or within a reasonable period, normally eight weeks. Three consequences of untimely decision-making by public authorities are distinguished. Firstly, an interested party can lodge an appeal with the administrative law court to order the administrative body to take a decision, as soon as the time period has expired and two weeks have passed since the interested party sent the administrative authority a written notice of default. Secondly, when these conditions are met, a penalty is forfeited for each day that no decision is taken. Thirdly and alternatively, a fictitious positive decision is deemed to have been taken. The chapter discusses the legal and practical consequences of these remedies

Verwaltungsverfahrens- und Personenstandsrecht als Konkretisierungsaufgabe

Der vorliegende Band dokumentiert die Vorträge, die auf einem am 15. November 2019 in Speyer veranstalteten Symposium gehalten wurden. Anlass dieser Veranstaltung, die vom Deutschen Forschungsinstitut für öffentliche Verwaltung und der Deutschen Universität für Verwaltungswissenschaften Speyer gemeinsam durchgeführt wurde, war die Verleihung der Ehrenmedaille des Deutschen Forschungsinstituts für öffentliche Verwaltung an Dr. Heribert Schmitz. Heribert Schmitz hat nicht nur als Vertreter des Bundes dem Verwaltungsrat des Instituts ab 1993 für 25 Jahre angehört und in dieser langen Zeit maßgeblich dazu beigetragen, dass sich das Institut konsolidiert und zu einem der maßgeblichen Akteure der deutschen Verwaltungswissenschaft entwickelt hat, sondern auch – weit hierüber hinausgehend – den Wissenschaftsstandort Speyer in seiner Gesamtheit in mannigfaltiger Hinsicht gefördert. Die Referenten des Symposiums und die Themen ihrer Beiträge sind eng verknüpft mit den verschiedenen Facetten des Wirkens von Heribert Schmitz, der seine Karriere im Bundes-ministerium des Innern im Jahre 1983 begann und ab 1993 in der Position des Leiters des Referats für Verwaltungsrecht, Verwaltungsverfahrensrecht und Informationsfreiheitsrecht, später auch Personenstandsrecht, fortsetzte. Das wissenschaftliche Wirken von Heribert Schmitz ist beeindruckend; genannt werden sollen hier nur seine großen Kommentierungen im Posser/Wolff zur VwGO und insbesondere im Stelkens/ Bonk/Sachs zum VwVfG. Das Anliegen, Wissenschaft und Praxis zu vernetzen, durchzieht sein gesamtes Wirken. Diesem vollständig gerecht zu werden, ist in dem begrenzten Rahmen eines Symposiums naturgemäß kaum möglich. Herausgeber und Autoren hoffen dennoch, dazu einen bescheidenen Beitrag zu leisten