Efficient inference, potential, and limitations of site-specific substitution models.

Natural selection imposes a complex filter on which variants persist in a population resulting in evolutionary patterns that vary greatly along the genome. Some sites evolve close to neutrally, while others are highly conserved, allow only specific states, or only change in concert with other sites. On one hand, such constraints on sequence evolution can be to infer biological function, one the other hand they need to be accounted for in phylogenetic reconstruction.

TreeTime: Maximum-likelihood phylodynamic analysis.

Mutations that accumulate in the genome of cells or viruses can be used to infer their evolutionary history. In the case of rapidly evolving organisms, genomes can reveal their detailed spatiotemporal spread. Such phylodynamic analyses are particularly useful to understand the epidemiology of rapidly evolving viral pathogens.

Estimating time of HIV-1 infection from next-generation sequence diversity.

Estimating the time since infection (TI) in newly diagnosed HIV-1 patients is challenging, but important to understand the epidemiology of the infection. Here we explore the utility of virus diversity estimated by next-generation sequencing (NGS) as novel biomarker by using a recent genome-wide longitudinal dataset obtained from 11 untreated HIV-1-infected patients with known dates of infection. The results were validated on a second dataset from 31 patients.

mutation rates and the landscape of fitness costs of HIV-1.

Mutation rates and fitness costs of deleterious mutations are difficult to measure but essential for a quantitative understanding of evolution. Using whole genome deep sequencing data from longitudinal samples during untreated HIV-1 infection, we estimated mutation rates and fitness costs in HIV-1 from the dynamics of genetic variation. At approximately neutral sites, mutations accumulate with a rate of 1.

Optimizing culture conditions for free-living stages of the nematode parasite Strongyloides ratti.

The rat parasitic nematode Strongyloides ratti (S. ratti) has recently emerged as a model system for various aspects of parasite biology and evolution. In addition to parasitic parthenogenetic females, this species can also form facultative free-living generations of sexually reproducing adults.