In many species that fight over resources, individuals use specialized structures to overpower their rivals (i.e. weapons). Despite their similar roles for contest settlement (i.e. affecting the winning chances), weapons are highly diverse morphological structures across species. However, the comprehension on how this diversity evolved is still open for debate. Unfortunately, most studies on how weapons are used during contests focus on size asymmetries between winners and losers. Although such information...
Thu Sep 03, 2020 03:00
The growing availability of genetic datasets, in combination with machine learning frameworks, offer great potential to answer long-standing questions in ecology and evolution. One such question has intrigued population geneticists, biogeographers, and conservation biologists: What determines intraspecific genetic diversity? This question is challenging to answer because many factors may influence genetic variation, including life history traits, historical influences, and geography, and the relative...
Thu Sep 03, 2020 03:00
Organisms differ in the types and numbers of tRNA genes that they carry. While the evolutionary mechanisms behind tRNA gene set evolution have been investigated theoretically and computationally, direct observations of tRNA gene set evolution remain rare. Here, we report the evolution of a tRNA gene set in laboratory populations of the bacterium Pseudomonas fluorescens SBW25. The growth defect caused by deleting the single-copy tRNA gene, serCGA, is rapidly compensated by large-scale (45-290 kb)...
Thu Sep 03, 2020 03:00
The vegetable ivory palms (Phytelepheae) form a small group of Neotropical palms whose phylogenetic relationships are not fully understood. Three genera and eight species are currently recognized; however, it has been suggested that Phytelephas macrocarpa could include the species Phytelephas seemannii and Phytelephas schottii because of supposed phylogenetic relatedness and similar morphology. We inferred their phylogenetic relationships and divergence time estimates using the 32 most clock-like...
Thu Sep 03, 2020 03:00
Whole genome sequences and coalescence theory allow the study of plant evolution in unprecedented detail. In this study we extend the genomic resources for the wild Mediterranean grass Brachypodium distachyon to investigate the scale of population structure and its underlying history at whole-genome resolution. The analysis of 196 accessions, spanning the Mediterranean from Iberia to Iraq, shows that the interplay of high selfing and seed dispersal rates has shaped genetic structure. At the continental...
Thu Sep 03, 2020 03:00
The Bering Land Bridge connecting North America and Eurasia was periodically exposed and inundated by oscillating sea levels during the Pleistocene glacial cycles. This land connection allowed the intermittent dispersal of animals, including humans, between Western Beringia (far north-east Asia) and Eastern Beringia (north-west North America), changing the faunal community composition of both continents. The Pleistocene glacial cycles also had profound impacts on temperature, precipitation, and vegetation,...
Thu Sep 03, 2020 03:00
ABSTRACT Telomere length is correlated positively with longevity at the individual level, but negatively when compared across species. Here, we tested the association between lifespan and telomere length in African annual killifish. We analyzed telomere length in 18 Nothobranchius strains derived from diverse habitats and measured the laboratory lifespan of 14 strains of N. furzeri and N. kadleci. We found that males had shorter telomeres than females. The longest telomeres were recorded in strains...
Thu Sep 03, 2020 03:00
There are two families of quantitative methods for inferring geographical homelands of language families: Bayesian phylogeography and the 'diversity method'. Bayesian methods model how populations may have moved using the backbone of a phylogenetic tree, while the diversity method, which does not need a tree as input, is based on the idea that the geographical area where linguistic diversity is highest likely corresponds to the homeland. No systematic tests of the performances of the different methods...
Thu Sep 03, 2020 03:00
Photosynthesis--both oxygenic and more ancient anoxygenic forms--has fueled the bulk of primary productivity on Earth since it first evolved more than 3.4 billion years ago. However, the early evolutionary history of photosynthesis has been challenging to interpret due to the sparse, scattered distribution of metabolic pathways associated with photosynthesis, long timescales of evolution, and poor sampling of the true environmental diversity of photosynthetic bacteria. Here, we reconsider longstanding...
Thu Sep 03, 2020 03:00
The relationship between microbiomes and selective regimes in the sponge genus Ircinia [NEW RESULTS]
Sponges are often densely populated by microbes that benefit their hosts through nutrition and bioactive secondary metabolites; however, sponges must simultaneously contend with the toxicity of microbes and thwart microbial overgrowth. Despite these fundamental tenets of sponge biology, the patterns of selection in the host sponges genomes that underlie tolerance and control of their microbiomes are still poorly understood. To elucidate these patterns of selection, we performed a population genetic...
Thu Sep 03, 2020 03:00
Phenotypic plasticity, the ability of an organism to express multiple phenotypes in response to the prevailing environmental conditions without genetic change, may occur as a response to anthropogenic environmental change. Arguably, the most significant future anthropogenic environment change is contemporary climate change. Given that increasing climate variability is predicted to pose a greater risk than directional climate change, we tested the effect of a water temperature differential of 4 {o}C...
Thu Sep 03, 2020 03:00
Cas9 trans-activating CRISPR RNAs (tracrRNAs) form distinct structures essential for target recognition and cleavage and dictate exchangeability between orthologous proteins. As non-coding RNAs that are often apart from the CRISPR array, their identification can be arduous. In this paper, a new bioinformatic method for the detection of Cas9 tracrRNAs is presented. The approach utilizes a co-variance model (CM) based on both sequence homology and predicted secondary structure to locate tracrRNAs....
Thu Sep 03, 2020 03:00
Lifestyle convergences and related phenotypes are a major topic in evolutionary biology. Low bone cortical compactness (CC), shared by the two genera of 'tree sloths', has been linked to their convergently evolved slow arboreal ecology. The proposed relationship of low CC with 'tree sloths' lifestyle suggests a potential convergent acquisition of this trait in other slow arboreal mammals. 'Tree sloths', 'Lorisidae', Palaeopropithecidae, Megaladapis and koalas were included in a phylogenetically informed...
Thu Sep 03, 2020 03:00
A central tenet of evolutionary theory is that it requires variation upon which selection can act. We describe a means of attaining cumulative, adaptive, open-ended change that requires neither variation nor selective exclusion, and that can occur in the absence of generations (i.e., no explicit birth or death). This second evolutionary process occurs through the assimilation, restructuring, and extrusion of products into the environment by identical, interacting Reflexively Autocatalytic and Food...
Thu Sep 03, 2020 03:00
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