9,410 research outputs found
Are there laws of genome evolution?
Research in quantitative evolutionary genomics and systems biology led to the
discovery of several universal regularities connecting genomic and molecular
phenomic variables. These universals include the log-normal distribution of the
evolutionary rates of orthologous genes; the power law-like distributions of
paralogous family size and node degree in various biological networks; the
negative correlation between a gene's sequence evolution rate and expression
level; and differential scaling of functional classes of genes with genome
size. The universals of genome evolution can be accounted for by simple
mathematical models similar to those used in statistical physics, such as the
birth-death-innovation model. These models do not explicitly incorporate
selection, therefore the observed universal regularities do not appear to be
shaped by selection but rather are emergent properties of gene ensembles.
Although a complete physical theory of evolutionary biology is inconceivable,
the universals of genome evolution might qualify as 'laws of evolutionary
genomics' in the same sense 'law' is understood in modern physics.Comment: 17 pages, 2 figure
Recommended from our members
Longitudinal survey of microbiome associated with particulate matter in a megacity.
BackgroundWhile the physical and chemical properties of airborne particulate matter (PM) have been extensively studied, their associated microbiome remains largely unexplored. Here, we performed a longitudinal metagenomic survey of 106 samples of airborne PM2.5 and PM10 in Beijing over a period of 6 months in 2012 and 2013, including those from several historically severe smog events.ResultsWe observed that the microbiome composition and functional potential were conserved between PM2.5 and PM10, although considerable temporal variations existed. Among the airborne microorganisms, Propionibacterium acnes, Escherichia coli, Acinetobacter lwoffii, Lactobacillus amylovorus, and Lactobacillus reuteri dominated, along with several viral species. We further identified an extensive repertoire of genes involved in antibiotic resistance and detoxification, including transporters, transpeptidases, and thioredoxins. Sample stratification based on Air Quality Index (AQI) demonstrated that many microbial species, including those associated with human, dog, and mouse feces, exhibit AQI-dependent incidence dynamics. The phylogenetic and functional diversity of air microbiome is comparable to those of soil and water environments, as its composition likely derives from a wide variety of sources.ConclusionsAirborne particulate matter accommodates rich and dynamic microbial communities, including a range of microbial elements that are associated with potential health consequences
Seasonal Niche Partitioning of Surface Temperate Open Ocean Prokaryotic Communities
Surface microbial communities are exposed to seasonally changing environmental conditions, resulting in recurring patterns of community composition. However, knowledge on temporal dynamics of open ocean microbial communities remains scarce. Seasonal patterns and associations of taxa and oligotypes from surface and chlorophyll maximum layers in the western Mediterranean Sea were studied over a 2-year period. Summer stratification versus winter mixing governed not only the prokaryotic community composition and diversity but also the temporal dynamics and co-occurrence association networks of oligotypes. Flavobacteriales, Rhodobacterales, SAR11, SAR86, and Synechococcales oligotypes exhibited contrasting seasonal dynamics, and consequently, specific microbial assemblages and potential inter-oligotype connections characterized the different seasons. In addition, oligotypes composition and dynamics differed between surface and deep chlorophyll maximum (DCM) prokaryotic communities, indicating depth-related environmental gradients as a major factor affecting association networks between closely related taxa. Taken together, the seasonal and depth specialization of oligotypes suggest temporal dynamics of community composition and metabolism, influencing ecosystem function and global biogeochemical cycles. Moreover, our results indicate highly specific associations between microbes, pointing to keystone ecotypes and fine-tuning of the microbes realized niche.En prens
- …