Publications de Séverine Vuilleumier Varisco

Size and duration of COVID-19 clusters go along with a high SARS-CoV-2 viral load: A spatio-temporal investigation in Vaud state, Switzerland

Séverine Vuilleumier Varisco, Stéphane Joost, Onya Opota, Anaïs Laurence Ladoy, Idris Guessous

To understand the geographical and temporal spread of SARS-CoV-2 during the first documented wave of infection in the state of Vaud, Switzerland, we analyzed clusters of positive cases using the precise residential location of 33,651 individuals tested (RT ...

2021

Indication of spatially random occurrence of Chlamydia-like organisms in Bufo bufo tadpoles from ponds located in the Geneva metropolitan area

Séverine Vuilleumier Varisco, Stéphane Joost, Oliver Michele Selmoni, Ivo Widmer, Elia Vajana

Occurrence of bacteria belonging to the order Chlamydiales was investigated for the first time in common toad (Bufo bufo) tadpole populations collected from 41 ponds in the Geneva metropolitan area, Switzerland. A Chlamydiales-specific real-time PCR was us ...

2019

Indication of spatially random infection of chlamydia-like organisms in Bufo bufo tadpoles from ponds located in the Geneva metropolitan area

Séverine Vuilleumier Varisco, Stéphane Joost, Estelle Rochat, Solange Catherine Gaillard, Oliver Michele Selmoni, Ivo Widmer, Elia Vajana

Occurrence of bacteria belonging to the order Chlamydiales was investigated for the first time in common toad (Bufo bufo) tadpole populations collected from 41 ponds in the Geneva metropolitan area, Switzerland. A Chlamydiales-specific Real-Time PCR was us ...

2018

A genetic reconstruction of the invasion of the calanoid copepod Pseudodiaptomus inopinus across the North American Pacific Coast

Séverine Vuilleumier Varisco, Susanne Petra Pfeifer

2018

Host shift and cospeciation rate estimation from co-phylogenies

Séverine Vuilleumier Varisco

Host shifts can cause novel infectious diseases, and is a key process in diversification. Disentangling the effects of host shift vs. those of cospeciation is non-trivial as both can result in phylogenic congruence. We develop a new framework based on netw ...

Wiley2017

Ecological strategies in stable and disturbed environments depend on species specialisation

Séverine Vuilleumier Varisco

Ecological strategies are integral to understanding species survival in different environments. However, how habitat specialisation is involved in such strategies is not fully understood, particularly in heterogeneous and disturbed environments. Here, we s ...

2016

Contribution of recombination to the evolutionary history of HIV

Séverine Vuilleumier Varisco

Purpose of review: An improved understanding of how recombination affects the evolutionary history of HIV is crucial to understand its current and future evolution. The present review aims to disentangle the manifold effects of recombination on HIV by disc ...

2015

The Genomic Signature of Population Reconnection Following Isolation: From Theory to HIV

Séverine Vuilleumier Varisco, Amalio Telenti, Jeffrey David Jensen

Ease of worldwide travel provides increased opportunities for organisms not only to colonize new environments but also to encounter related but diverged populations. Such events of reconnection and secondary contact of previously isolated populations are w ...

Genetics Society of America2015

On the transition of genetic differentiation from isolation to panmixia: What we can learn from G(ST) and D

Séverine Vuilleumier Varisco

Population genetic differentiation characterizes the repartition of alleles among populations. It is commonly thought that genetic differentiation measures, such as G(ST) and D, should be near zero when allele frequencies are close to their expected value ...

Elsevier2014

Turnover and accumulation of genetic diversity across large time-scale cycles of isolation and connection of populations

Séverine Vuilleumier Varisco

Major climatic and geological events but also population history (secondary contacts) have generated cycles of population isolation and connection of long and short periods. Recent empirical and theoretical studies suggest that fast evolutionary processes ...

2014

Coexistence of specialist and generalist species is shaped by dispersal and environmental factors

Séverine Vuilleumier Varisco

Disentangling the mechanisms mediating the coexistence of habitat specialists and generalists has been a long-standing subject of investigation. However, the roles of species traits and environmental and spatial factors have not been assessed in a unifying ...

2014

Uncovering the genetic basis of adaptive change: on the intersection of landscape genomics and theoretical population genetics

Séverine Vuilleumier Varisco, Stéphane Joost, Sylvie Stucki, Kevin Leempoel, Jeffrey David Jensen, Ivo Widmer

A workshop recently held at the École Polytechnique Fédérale de Lausanne (EPFL, Switzerland) was dedicated to understanding the genetic basis of adaptive change, taking stock of the different approaches developed in theoretical population genetics and land ...

Wiley-Blackwell2013

Invasion and eradication of a competitively superior species in heterogeneous landscapes

Séverine Vuilleumier Varisco, Alexandre Buttler, Nicolas Perrin

The effect of heterogeneous environments upon the dynamics of invasion and the eradication or control of invasive species is poorly understood, although it is a major challenge for biodiversity conservation. Here, we first investigate how the probability a ...

Elsevier2011

Positive feedback in the transition from sexual reproduction to parthenogenesis

Séverine Vuilleumier Varisco

Understanding how new phenotypes evolve is challenging because intermediate stages in transitions from ancestral to derived phenotypes often remain elusive. Here we describe and evaluate a new mechanism facilitating the transition from sexual reproduction ...

2010

Effects of Colonization Asymmetries on Metapopulation Persistence

Séverine Vuilleumier Varisco, Olivier Lévêque

Ocean currents, prevailing winds, and the hierarchical structures of river networks are known to create asymmetries in re-colonization between habitat patches. The impacts of such asymmetries on metapopulation persistence are seldom considered, especially ...

Elsevier2010

The fixation of locally beneficial alleles in a metapopulation

Séverine Vuilleumier Varisco, Nicolas Perrin

Extinction, recolonization and local adaption are common in natural spatially structured populations. Understanding their effect upon genetic variation is important for systems such as GMO management, or avoidance of drug resistance. Theoretical studies on ...

2008

Landscape structure affects dispersal in the greater white-toothed shrew: inference between genetic and simulated ecological distances

Séverine Vuilleumier Varisco

Dispersal is often viewed as a process on which the landscape has little effect. This is particularly apparent in populations’ genetic and ecological studies, where isolation by distance is generally tested using a Euclidean distance between populations. H ...

Elsevier2007

Invasion an fixation of sex-reversal genes

Séverine Vuilleumier Varisco

We simulated a meta-population with random dispersal among demes but local mating within demes to investigate conditions under which a dominant female-determining gene W, with no individual selection advantage, can invade and become fixed in females, chang ...

Wiley-Blackwell2007

Effects of cognitives abilities on metapopulation connectivity

Séverine Vuilleumier Varisco, Nicolas Perrin

Connectivity among demes in a metapopulation depends on both the landscape's and the focal organism's properties (including its mobility and cognitive abilities). Using individual-based simulations, we contrast the consequences of three different cognitive ...

2006

Animal dispersal modelling: handling landscape features and related animal choices

Richard Metzger, Séverine Vuilleumier Varisco

Animal dispersal in a fragmented landscape depends on the complex interaction between landscape structure and animal behavior. To better understand how individuals disperse, it is important to explicitly represent the properties of organisms and the landsc ...

Elsevier2006