The evolution, diversity and host associations of rhabdoviruses

The evolution, diversity and host associations of rhabdoviruses

Ben Longdon, Gemma GR Murray, William J Palmer, Jonathan P Day, Darren J Parker, John J Welch, Darren J Obbard, Francis M Jiggins

The impact of host metapopulation structure on the population genetics of colonizing bacteria

The impact of host metapopulation structure on the population genetics of colonizing bacteria

Elina Numminen, Michael U Gutmann, Mikhail Shubin, Pekka Marttinen, Guillaume Meric, Willem van Schaik, Teresa Coque, Fernando Baquero, Rob Willems, Samuel K Sheppard, Edward J Feil, William P Hanage, Jukka Corander

Evolutionary assembly patterns of prokaryotic genomes

Evolutionary assembly patterns of prokaryotic genomes

Maximilian Press, Christine Queitsch, Elhanan Borenstein

Fractality and Entropic Scaling in the Chromosomal Distribution of Conserved Noncoding Elements in the Human Genome

Fractality and Entropic Scaling in the Chromosomal Distribution of Conserved Noncoding Elements in the Human Genome

Dimitris Polychronopoulos, Labrini Athanasopoulou, Yannis Almirantis

On the causes of evolutionary transition:transversion bias

On the causes of evolutionary transition:transversion bias

Arlin Stoltzfus, Ryan W. Norris

Evolution of complex phenotypes through successions of adaptive steps

Evolution of complex phenotypes through successions of adaptive steps
Tin Y. Pang, Martin Lercher

The emergence of complex phenotype is a fascinating question of evolutionary biology, and we sought to understand preadaptation which facilitated the development of complex phenotypes, in the context of bacterial metabolic network. Genes coordinated for a phenotype are likely to cluster on the same place of the genome, which so allows horizontal gene transfer (HGT) to pass the phenotype to another bacterium. But for a complex phenotype, its genes are clustered on different places of the genome cannot be transferred adaptively; it is preadaptation, which refers to adaptive transfer of a segment relevant to a complex phenotype for other purposes, that allows it later to be recruited for the complex phenotype. To search for preadaptation in the evolutionary history of E. coli, we reconstructed the ancestral genomes from various strains, identified the transferred genes, grouped them into possible transferred segments, and analyzed the gains in nutritional phenotypes corresponding to the acquisitions of segments of metabolic genes. Properties of these HGT segments inferred from data are enumerated and compared with a model of HGT, which shows that: 1) HGT segments are likely to adaptive, and segments carrying reactions essential to phenotypic gains but non-adaptive are rare; 2) the landscape of segment transfer for complex phenotypes is directional and path-dependent; 3) cooperation between HGT segments to support various nutritional phenotypes are observed to be more frequent than expected, which serves as an evidence to preadaptation in the evolution of bacterial metabolic network.

Wolbachia infection in a sex-structured mosquito population carrying West Nile virus

Wolbachia infection in a sex-structured mosquito population carrying West Nile virus
József Z. Farkas, Stephen A. Gourley, Rongsong Liu, Abdul-Aziz Yakubu

Wolbachia is possibly the most studied reproductive parasite of arthropod species. It appears to be a promising candidate for biocontrol of some mosquito borne diseases. We begin by developing a sex-structured model for a Wolbachia infected mosquito population. Our model incorporates the key effects of Wolbachia infection including cytoplasmic incompatibility and male killing. We also allow the possibility of reduced reproductive output, incomplete maternal transmission, and different mortality rates for uninfected/infected male/female individuals. We study the existence and local stability of equilibria, including the biologically relevant and interesting boundary equilibria. For some biologically relevant parameter regimes there may be multiple coexistence steady states including, very importantly, a coexistence steady state in which Wolbachia infected individuals dominate. We also extend the model to incorporate West Nile virus (WNv) dynamics, using an SEI modelling approach. Recent evidence suggests that a particular strain of Wolbachia infection significantly reduces WNv replication in Aedes aegypti. We model this via increased time spent in the WNv-exposed compartment for Wolbachia infected female mosquitoes. A basic reproduction number R0 is computed for the WNv infection. Our results suggest that, if the mosquito population consists mainly of Wolbachia infected individuals, WNv eradication is likely if WNv replication in Wolbachia infected individuals is sufficiently reduced.