A dynamic continuum exists from free-living environmental microbes to strict host associated symbionts that are vertically inherited. However, knowledge of the forces that drive transitions in the modes by which symbioses form is lacking. Arsenophonus is a diverse clade of bacterial symbionts, comprising reproductive parasites to coevolving obligate mutualists, in which the predominant mode of transmission is vertical. We describe a symbiosis between a member of the genus Arsenophonus and the Western...
Wed Jul 29, 2020 03:00
Arbuscular mycorrhizal fungi (AMF) are widespread microfungi that provide mineral nutrients to most land plants and form one of the oldest terrestrial symbioses. They have often been referred to as an "evolutionary cul-de-sac" for their limited ecological and species diversity. Here we use a global database of AMF to analyze their diversification dynamics in the past 500 million years (Myr). We find that AMF have low diversification rates. After a diversification peak around 150 Myr ago, they experienced...
Wed Jul 29, 2020 03:00
Ecological divergence is a main source of trait differences between closely related species. Despite its importance in generating biodiversity, the genetic architecture of most ecologically relevant traits is poorly understood. In plants, differences in elevation can impose substantial selection for phenotypic divergence of both complex, correlated suites of traits (such as life history), as well as novel adaptations. Here, we use the Mimulus guttatus species complex to assess if divergence in elevation...
Wed Jul 29, 2020 03:00
Non-iridescent, structurally-based coloration in birds originates from the feather's internal nanostructure (the keratin spongy matrix), but the presence of melanin and the characteristics of the barb's cortex can affect the resulting color. Here we investigate how this nanostructure is regulated and combined with other elements in differently-colored plumage patches. To do so, we investigated the association between light reflectance and the morphology of feathers from the back and belly plumage...
Wed Jul 29, 2020 03:00
Microorganisms produce materials leaked from the cell which are beneficial for themselves and their neighbors. We modeled the situation when cells can produce different costly secretions which increase the carrying capacity of the population. Strains that lose the function of producing one or more secretions avoid the cost of production and can exhaust the producers. However, secreting substances provides a private benefit for the producers in a density-dependent way. We developed a model to examine...
Wed Jul 29, 2020 03:00
Species divergence is facilitated when traits under divergent selection also act as mating cues. Fluctuations in sensory conditions can alter signal perception independently of adaptation to contrasting sensory environments, but how this fine scale variation affects behavioural isolation has received less attention, especially in terrestrial organisms. The warning patterns of Heliconius butterflies are under selection for aposematism and act as mating cues. Using computer vision, we extracted behavioural...
Wed Jul 29, 2020 03:00
Sex differences in behavioral traits are common, but we know little about the role of sexual selection in shaping these traits. Estimating sex-specific genetic effects and cross-sex genetic correlations can provide insights into sex-specific selection and on whether evolution can shape independent expression of behavioral traits across the sexes. We conducted a quantitative genetic study in a sexually-size-dimorphic spider, Larinioides sclopetarius, which exhibits sex differences in adult life-styles....
Wed Jul 29, 2020 03:00
Numerous studies of emerging species have identified genomic "islands" of elevated differentiation against a background of relative homogeneity. The causes of these islands remain unclear, however, with some signs pointing toward "speciation genes" that locally restrict gene flow and others suggesting selective sweeps that have occurred within nascent species after speciation. Here, we examine this question through the lens of genome sequence data for five species of southern capuchino seedeaters,...
Wed Jul 29, 2020 03:00
The uniquely enlarged noses of male proboscis monkeys (Nasalis larvatus) are prominent adornments, and a sexually selected male masculine trait. A recent study showed the significant correlations among nose, body, and testis sizes and the clear association between nose size and the number of females in a male's harem. However, to date, the analyses of other common male traits, i.e., canines, are lacking. Whereas male nose size had a positive correlation with body size, we unexpectedly found a negative...
Wed Jul 29, 2020 03:00
Intra-protein residual vicinities depend on the involved amino acids. Energetically favorable vicinities (or interactions) have been preserved during evolution, while unfavorable vicinities have been eliminated. We describe, statistically, the interactions between amino acids using resolved protein structures. Based on the frequency of amino acid interactions, we have devised an amino acid substitution model that implements the following idea: amino acids that have similar neighbors in the protein...
Wed Jul 29, 2020 03:00
Background. Triatomine bugs, the vectors of Chagas disease, associate with vertebrate hosts in highly diverse ecotopes. When these blood-sucking bugs adapt to new microhabitats, their phenotypes may change. Although understanding phenotypic variation is key to the study of adaptive evolution and central to phenotype-based taxonomy, the drivers of phenotypic change and diversity in triatomines remain poorly understood. Methods/Findings. We combined a detailed phenotypic appraisal (including morphology...
Tue Jul 28, 2020 03:00
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου