Previously we performed a 1012-generation mutation accumulation (MA) study in yeast and found that a surprisingly large proportion of fitness-altering mutations were beneficial. To verify this result and assess the impact of sampling error in our previous study, we have continued the MA experiment for an additional 1050 cell generations and re-estimated mutation parameters. After correcting for...

A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation, and selection, is studied, using mean-field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transition between extinction due to random drift and survival. For weak selection th...

A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental fact...

There is growing interest in understanding how kin selection drives the evolution of social behaviours in viscous populations. A key result, that has inspired much work on this topic, is the exact cancellation of the genetic relatedness and kin competition effects of dispersal in the simplest models of population viscosity, such that a reduction in the rate of dispersal neither promotes nor inh...

Saccharomyces cerevisiae strain M3707 was isolated from a sample of commercial distillers yeast, and its genome sequence together with the genome sequences for the four derived haploid strains M3836, M3837, M3838, and M3839 has been determined. Yeasts have potential for consolidated bioprocessing (CBP) for biofuel production, and access to these genome sequences will facilitate their development.

Under models of isolation-by-distance, population structure is determined by the probability of identity-by-descent between pairs of genes according to the geographic distance between them. Well established analytical results indicate that the relationship between geographical and genetic distance depends mostly on the neighborhood size of the population which represents a standardized measure ...

We present here a self-contained analytic review of the role of stochastic factors acting on a virus population. We develop a simple one-locus, two-allele model of a haploid population of constant size including the factors of random drift, purifying selection, and random mutation. We consider different virological experiments: accumulation and reversion of deleterious mutations, competition be...

Prospects for a comprehensive inventory of global biodiversity would be greatly improved by automating methods of species delimitation. The general mixed Yule-coalescent (GMYC) was recently proposed as a potential means of increasing the rate of biodiversity exploration. We tested this method with simulated data and applied it to a group of poorly known bats (Hipposideros) from the Philippines....

Evolutionary adaptation is often likened to climbing a hill or peak. While this process is simple for fitness landscapes where mutations are independent, the interaction between mutations (epistasis) as well as mutations at loci that affect more than one trait (pleiotropy) are crucial in complex and realistic fitness landscapes. We investigate the impact of epistasis and pleiotropy on adaptive ...

The evolutionary effect of recombination depends crucially on the epistatic interactions between linked loci. A paradigmatic case where recombination is known to be strongly disadvantageous is a two-locus fitness landscape displaying reciprocal sign epistasis with two fitness peaks of unequal height. Although this type of model has been studied since the 1960s, a full analytic understanding of ...