Under the selfish centromere model, costs associated with female meiotic drive by centromeres select on interacting kinetochore proteins to restore Mendelian inheritance. We directly test this model in yellow monkeyflowers (Mimulus guttatus), which are polymorphic for a costly driving centromere (D). We show that the D haplotype is structurally and genetically distinct and swept to a high stable frequency within the past 1500 years. Quantitative genetic analyses reveal that variation in the strength of drive...

Egg development is a defining process of reproduction in higher eukaryotes. In the fruit fly, Drosophila melanogaster, this process begins with four mitotic divisions starting from a single germ cell, producing a cyst of 16 cystocytes; one of these cells will become the oocyte and the others supporting nurse cells. These mitotic divisions are exceptional because cytokinesis is incomplete, resulting in the formation of cytoplasmic bridges known as ring canals that interconnect the cystocytes. This...

Nocturnality is widespread among extant mammals and often considered the ancestral behavioural pattern for all mammals. However, mammals are nested within a larger clade, Synapsida, and non-mammalian synapsids comprise a rich phylogenetic, morphological and ecological diversity. Even though non-mammalian synapsids potentially could elucidate the early evolution of diel activity patterns and enrich the understanding of synapsid palaeobiology, data on their diel activity are currently unavailable. Using scleral ring and orbit dimensions, we demonstrate that nocturnal...

Questions: 1) How did seedling numbers and species composition change in the first year after a wildfire during drought, relative to pre-fire variation? 2) Has the community returned to pre-fire composition after five years? 3) Has the degree of dominance by exotic annual grasses changed? 4) Is there any evidence that drought conditions affected community cover, before or after fire? Location: Exotic-dominated annual grassland in southern California, U.S.A. Methods: We monitored community cover and native...

Sensory uncertainties and imperfections in motor control play important roles in neural control and Bayesian approaches to neural encoding. However, it is diffcult to estimate these uncertainties experimentally. Here we show that magnitude of the uncertainties during the generation of motor control force can be measured for a virtual stick balancing task by varying the feedback delay, tau . It is shown that the shortest stick length that human subjects are able to balance is...

Geckos feature a large range of eye sizes, but what drives this phenotypic diversity is currently unknown. Earlier studies point towards diel activity patterns (DAP) and locomotory mode, but phylogenetic comparative studies in support of the proposed adaptive mode of eye evolution are lacking. Here we test the hypothesis of DAP as the driver of eye size evolution with a dataset on 99 species of gecko. Results from phylogenetic generalized least square analysis (PGLS) and...

Pathogen interactions arising during coinfection can exacerbate disease severity, for example, when the immune response mounted against one pathogen negatively affects defense of another. It is also possible that host immune responses to a pathogen, shaped by historical evolutionary interactions between host and pathogen, may modify host immune defenses in ways that have repercussions for other pathogens. In this case, negative interactions between two pathogens could emerge even in the absence of concurrent infection. Parasitic...