Biology subjects

Vitali, V.

Publications and source records attributed to Vitali, V..

7 recordsLinked to original sources

bioRxiv2026

Adaptive variation in drought-related traits across southern and central European white oak (Quercus sect. Quercus) populations

European white oaks grow from the Mediterranean coast to Southern Scandinavia, a huge environmental gradient that has likely fostered environmental adaptation. In the face of climate change, leveraging adaptations through assisted gene flow could help improve drought tolerance and maintain forest health, but requires an understanding of the species-specific patterns of adaptation to be successful at the target location. In this study, three common gardens were established in Switzerland, Tuerkiye, and Austria for two European white oak species (Quercus robur, and Q. pubescens) using provenances from Central and Southern Europe. Almost 900 oak seedlings were measured at key water-use efficiency and life history traits for their first two year of life and genotyped with low coverage whole-genome sequencing. Trait heritability and environmental adaptation were then explored through pedigree-free animal models, while the genomic architecture of traits was mapped using a genome wide association study ("GWAS"). Across the species, the heritability of measured traits was moderate to high, but common garden had a strong impact, signalling an environmental effect on the phenotype. Adaptation to precipitation seasonality was detected in key productivity and growth traits for both species, but had a small effect on absolute trait values. The GWAS identified a striking 150 kbp association in the Cyclic Nucleotide-Gated Ion Channel gene family with leaf d13C values. This gene family is involved in stomata opening and likely impacts the intrinsic water use efficiency under stress. Together, the strong signals of phenotypic plasticity and rather weak signals of climatic adaptation in seedlings suggest that assisted gene flow in these two white oaks is relevant only for highly drought-sensitive populations, if conducted managers should focus on seeds sources with high precipitation seasonality and smaller leaf sizes.

evolutionary biology↗

bioRxiv2025

A developmental condensin I complex assists the Paramecium PiggyMac domesticated transposase during programmed DNA elimination

Prokaryotes and eukaryotes use diverse strategies to cope with invading mobile genetic elements, including programmed DNA elimination (PDE). In the ciliate Paramecium, elimination of transposable elements and their relics requires the PiggyMac (Pgm) endonuclease and its five PgmL partners, yet how this machinery is targeted to cleavage sites remains unclear. Here, we identified condensin I subunits in the proximity proteomes of Pgm and PgmL4. We show that they belong to a condensin complex that is essential for PDE and localizes to developing somatic nuclei. Depleting the development-specific subunits of this complex blocks DNA elimination, phenocopying a Pgm depletion. Developmental condensin is required for the correct nuclear localization of Pgm and some of the PgmLs. Moreover, Pgm and these PgmLs co-immunoprecipitate with condensin I. Our findings uncover functional and physical interactions between a eukaryotic DNA cleavage machinery and a specialized condensin complex that is critical for PDE in a non-dividing nucleus.

molecular biology↗

bioRxiv2021

Fifty generations of amitosis: tracing asymmetric allele segregation in polyploid cells with single-cell DNA sequencing

Amitosis is a widespread form of unbalanced nuclear division whose biomedical and evolutionary significance remain unclear. Traditionally, insights into the genetics of amitosis are acquired by assessing the rate of phenotypic assortment. The phenotypic diversification of heterozygous clones during successive cell divisions reveals the random segregation of alleles to daughter nuclei. Though powerful, this experimental approach relies on the availability of phenotypic markers. Here, we present an approach that overcomes the requirement for phenotypic assortment. Leveraging Paramecium tetraurelia, a unicellular eukaryote with nuclear dimorphism and a highly polyploid somatic nucleus, we use single-cell whole-genome sequencing to track the assortment of developmentally acquired somatic DNA variants. Accounting for genome representation biases, we measure the effect of amitosis on allele segregation across the first [~]50 amitotic divisions post self-fertilization and compare our empirical findings with theoretical predictions estimated via mathematical modeling. In line with our simulations, we show that amitosis in P. tetraurelia produces measurable but modest levels of somatic assortment. In forgoing the requirement for phenotypic assortment and employing developmental, environmentally induced somatic variation as molecular markers, our work provides a new powerful approach to investigate the consequences of amitosis in polyploid cells.

genomics↗

bioRxiv2021

Individuality, as well as genotype, affects characteristics and temporal consistency of courtship songs in male mice

Courtship songs in mice have been investigated to understand the mechanisms and ecological relevance of vocal communication. There is evidence that courtship song characteristics vary between different genotypes, but little is known on whether individuals, even within the same genotype, differ from each other in the composition, complexity, and temporal consistency of their songs. In a first study, we aimed to systematically identify song features typical of different genotypes, by assessing the composition and complexity (i.e., entropy) of the syllabic sequences of male laboratory mice from four different strains (Mus musculus f. domestica: C57BL/6J, BALB/c, DBA/2 and B6D2F1). Mice were individually presented with a swab containing fresh female urine for 5 minutes to elicit courtship songs. The four strains differed not only in the composition but also in the complexity of their syllabic sequences. In a second study, we investigated within-strain individual differences in temporal consistency and recurring motifs (i.e., identical sets of syllables that are repeated within a song), using BALB/c and DBA/2 mice. The same procedure as in the first study was followed, but in addition testing was repeated weekly over three weeks. Both strains showed some level of individual temporal consistency; BALB/c in the overall amount of emitted vocalisations and DBA/2 in the expression of specific syllable types. However, hierarchical cluster analysis revealed remarkable individual variability in how consistent song characteristics were over time. Furthermore, recurring motifs were expressed at varying levels depending on the individual. Taken together, not only genotype but also individuality can affect variability in courtship songs in mice, suggesting the existence of different courtship strategies (e.g., higher song consistency to facilitate individual identification) related to varying levels of behavioural plasticity. HIGHLIGHTSO_LICourtship songs in mice can serve as a model to study vocal communication C_LIO_LIWe explore how genotype and individuality affect courtship songs characteristics C_LIO_LIGenotypes differ in composition and also in complexity of syllabic sequences C_LIO_LIWe find remarkable individual variability in how consistent songs are over time C_LIO_LIResults suggest the existence of variation in male courting behaviour C_LI

animal behavior and cognition↗

bioRxiv2020

Prolonged exposure to constant environmental conditions prompts nonrandom genetic variation

Long-term environmental exposure under selection-free conditions has no consequences for fitness under the neo-Darwinian paradigm but it may provoke adaptive developmental buffering if environmental pressures foster directional organismal changes. To test this hypothesis, we revisited a Mutation Accumulation (MA) experiment where isogenic lines of the ciliate Paramecium were propagated for >40 sexual cycles ([~]4 years) in a nearly selection-free and nutrient-rich environment. We find that these MA lines somatic genome is enriched with intervening segments of DNA (IESs), which are normally eliminated during germline-soma differentiation. Across independent replicate MA lines, an excess of these somatic IESs fall into a class of epigenetically controlled sequences, map to the same genomic locations, and preferentially disrupt loci that regulate nutrient metabolism. Although further work is needed to assess the phenotypic consequences of somatic IESs, these findings support a model where environmentally induced developmental variants may restore an adaptive fit between phenotype and environment. In this model, positive selection is surprisingly dispensable for adaptation.

evolutionary biology↗

bioRxiv2019

Sex enhances survival in Paramecium

The pervasiveness of sex despite its well-known costs is a long-standing puzzle in evolutionary biology. Current explanations for the success of sex in nature largely rely on the adaptive significance of the new or rare genotypes that sex may generate. Less explored is the possibility that sex-underlying molecular mechanisms can enhance fitness and convey benefits to the individuals that bear the immediate costs of sex. Here we show that self-fertilization can increase stress resistance in the ciliate Paramecium tetraurelia. This advantage is independent of new genetic variation, coupled with a reduced nutritional input, and offers fresh insights into the mechanistic origin of sex. In addition to providing evidence that the molecular underpinnings of sexual reproduction and the stress response are linked in P. tetraurelia, these findings supply an explanation for the persistence of self-fertilization in this ciliate.

evolutionary biology↗

bioRxiv2018

Enhanced plasticity of programmed DNA elimination boosts adaptive potential in suboptimal environments

The impact of ecological changes on the development of new somatic genomes has thus far been neglected. This oversight yields an incomplete understanding of the mechanisms that underlie environmental adaptation and can be tackled leveraging the biological properties of ciliates. When Paramecium reproduces sexually, its polyploid somatic genome regenerates from the germline genome via a developmental process, Programmed DNA elimination (PDE), that involves the removal of thousands of ORF-interrupting germline sequences. Here, we demonstrate that exposure to sub-optimal temperatures impacts PDE efficiency, prompting the emergence of hundreds of alternative DNA splicing variants that dually embody cryptic (germline) variation and de novo induced (somatic) mutations. In contrast to trivial biological errors, many of these alternative DNA isoforms display a patterned genomic topography, are epigenetically controlled, inherited trans-somatically, and under purifying selection. Developmental thermoplasticity in Paramecium is a likely source of evolutionary innovation.

evolutionary biology↗