OMA is an established resource to elucidate evolutionary relationships among genes from currently 2326 genomes covering all domains of life. OMA provides pairwise and groupwise orthologs, functional annotations, local and global gene order conservation (synteny) information, among many other functions. This update paper describes the reorganisation of the database into gene-, group- and genome-centric pages. Other new and improved features are detailed, such as reporting of the evolutionarily best conserved isoforms of alternatively spliced genes, the inferred local order of ancestral genes, phylogenetic profiling, better cross-references, fast genome mapping, semantic data sharing via RDF, as well as a special coronavirus OMA with 119 viruses from the Nidovirales order, including SARS-CoV-2, the agent of the COVID-19 pandemic. We conclude with improvements to the documentation of the resource through primers, tutorials and short videos. OMA is accessible at https://omabrowser.org.
Clownfishes are an iconic group of coral reef fishes, especially known for their mutualism with sea anemones. This mutualism is particularly interesting as it likely acted as the key innovation that triggered clownfish adaptive radiation. Indeed, after the acquisition of the mutualism, clownfishes diversified into multiple ecological niches linked with host and habitat use. However, despite the importance of this mutualism, the genetic mechanisms allowing clownfishes to interact with sea anemones are still unclear. Here, we used a comparative genomics and molecular evolutionary analyses to investigate the genetic basis of clownfish mutualism with sea anemones. We assembled and annotated the genome of nine clownfish species and one closely related outgroup. Orthologous genes inferred between these species and additional publicly available teleost genomes resulted in almost 16,000 genes that were tested for positively selected substitutions potentially involved in the adaptation of clownfishes to live in sea anemones. We identified 17 genes with a signal of positive selection at the origin of clownfish radiation. Two of them (Versican core protein and Protein O-GlcNAse) show particularly interesting functions associated with N-acetylated sugars, which are known to be involved in sea anemone discharge of toxins. This study provides the first insights into the genetic mechanisms of clownfish mutualism with sea anemones. Indeed, we identified the first candidate genes likely to be associated with clownfish protection form sea anemones, and thus the evolution of their mutualism. Additionally, the genomic resources acquired represent a valuable resource for further investigation of the genomic basis of clownfish adaptive radiation.
New World monkeys (platyrrhines) are one of the most diverse groups of primates, occupying today a wide range of ecosystems in the American tropics and exhibiting large variations in ecology, morphology, and behavior. Although the relationships among the almost 200 living species are relatively well understood, we lack robust estimates of the timing of origin, ancestral morphology, and geographic range evolution of the clade. Here we integrate paleontological and molecular evidence to assess the evolutionary dynamics of extinct and extant platyrrhines. We develop novel analytical frameworks to infer the evolution of body mass, changes in latitudinal ranges through time, and species diversification rates using a phylogenetic tree of living and fossil taxa. Our results show that platyrrhines originated 5-10 million years earlier than previously assumed, dating back to the Middle Eocene. The estimated ancestral platyrrhine was small - weighing 0.4 kg - and matched the size of their presumed African ancestors. As the three platyrrhine families diverged, we recover a rapid change in body mass range. During the Miocene Climatic Optimum, fossil diversity peaked and platyrrhines reached their widest latitudinal range, expanding as far South as Patagonia, favored by warm and humid climate and the lower elevation of the Andes. Finally, global cooling and aridification after the middle Miocene triggered a geographic contraction of New World monkeys and increased their extinction rates. These results unveil the full evolutionary trajectory of an iconic and ecologically important radiation of monkeys and showcase the necessity of integrating fossil and molecular data for reliably estimating evolutionary rates and trends.
The shift from sexual reproduction to parthenogenesis has occurred repeatedly in animals, but how the loss of sex affects genome evolution remains poorly understood. We generated reference genomes for five independently evolved parthenogenetic species in the stick insect genus Timema and their closest sexual relatives. Using these references and population genomic data, we show that parthenogenesis results in an extreme reduction of heterozygosity and often leads to genetically uniform populations. We also find evidence for less effective positive selection in parthenogenetic species, suggesting that sex is ubiquitous in natural populations because it facilitates fast rates of adaptation. Parthenogenetic species did not show increased transposable element (TE) accumulation, likely because there is little TE activity in the genus. By using replicated sexual-parthenogenetic comparisons, our study reveals how the absence of sex affects genome evolution in natural populations, providing empirical support for the negative consequences of parthenogenesis as predicted by theory.
Clownfishes (or anemonefishes) form an iconic group of coral reef fishes, principally known for their mutualistic interaction with sea anemones. They are characterized by particular life history traits, such as a complex social structure and mating system involving sequential hermaphroditism, coupled with an exceptionally long lifespan. Additionally, clownfishes are considered to be one of the rare groups to have experienced an adaptive radiation in the marine environment. Here, we assembled and annotated the first genome of a clownfish species, the tomato clownfish (Amphiprion frenatus). We obtained 17,801 assembled scaffolds, containing a total of 26,917 genes. The completeness of the assembly and annotation was satisfying, with 96.5% of the Actinopterygii Benchmarking Universal Single-Copy Orthologs (BUSCOs) being retrieved in A. frenatus assembly. The quality of the resulting assembly is comparable to other bony fish assemblies. This resource is valuable for advancing studies of the particular life history traits of clownfishes, as well as being useful for population genetic studies and the development of new phylogenetic markers. It will also open the way to comparative genomics. Indeed, future genomic comparison among closely related fishes may provide means to identify genes related to the unique adaptations to different sea anemone hosts, as well as better characterize the genomic signatures of an adaptive radiation.
The shift from sexual reproduction to parthenogenesis has occurred repeatedly in animals, but how the loss of sex affects genome evolution remains poorly understood. We generated de novo reference genomes for five independently evolved parthenogenetic species in the stick insect genus Timema and their closest sexual relatives. Using these references in combination with population genomic data, we show that parthenogenesis results in an extreme reduction of heterozygosity, and often leads to genetically uniform populations. We also find evidence for less effective positive selection in parthenogenetic species, supporting the view that sex is ubiquitous in natural populations because it facilitates fast rates of adaptation. Contrary to studies of non-recombining genome portions in sexual species, genomes of parthenogenetic species do not accumulate transposable elements (TEs), likely because successful parthenogens derive from sexual ancestors with inactive TEs. Because we are able to conduct replicated comparisons across five species pairs, our study reveals, for the first time, how animal genomes evolve in the absence of sex in natural populations, providing empirical support for the negative consequences of parthenogenetic reproduction as predicted by theory.
Objective To study the occurrence of autonomic hyper-all cases. Five patients showed a decrease in heart rate during the increase in blood pressure. However, in reflexia (AHR) after intradural sacral posterior rhizotomy combined with intradural sacral anterior root three patients the heart rate did not change or even sometimes slightly increased as the arterial blood stimulation, performed to manage the neurogenic hyper-reflexic bladder, and to determine the pathophy-pressure exceeded 160 mmHg, when the blood pressure and heart rate then increased together. siological basis of the uncontrolled hypertensive crisis after sacral de-aCerentation.Conclusions These results confirm that even after complete sacral de-aCerentation, AHR persisted in patients Patients and methods Ten patients with spinal cord injury operated using Brindley's method between with spinal cord injury and always occurred during the stimulation-induced voiding phase. In cases of September 1990 and February 1994 were reviewed. Systematic continuous non-invasive recordings of incomplete de-aCerentation, small uninhibited bladder contractions without voiding occurred during the fill-cardiovascular variables (using a photoplethysmograph) were made during urodynamic recordings and ing phase. The blood pressure then increased but never reached the value recorded during stimulation-the pre-and post-operative vesico-urethral and cardiovascular data compared.induced micturition. Stimulation of aCerents that enter the spinal cord by the thoracic and lumbar roots and Results Nine of the 10 patients were examined using a new prototype measurement system; one woman that are not influenced by sacral rhizotomy could explain why AHR increases during urine flow. The refused the last urodynamic assessment. Eight of the nine patients who presented with AHR before oper-distinct threshold of decreased heart rate by increasing blood pressure to >160 mmHg focuses attention on ation still had the condition afterward. There was a marked elevation in systolic and diastolic blood the chronotropic influences of the sympathetic nerves in the heart by an exhausted baroreceptor reflex. pressure during the urodynamic examination in all eight patients, despite complete intra-operative Keywords Autonomic hyper-reflexia, urodynamics, neurogenic bladder, spinal cord injury, sacral root de-aCerentation of the bladder in five. The elevation of blood pressure started during the stimulation-induced stimulation bladder contractions and increased during voiding in tract or from the rectum because of rectal impaction.
Assessing the quality of protein-coding gene repertoires is critical in an era of increasingly abundant genome sequences for a diversity of species. State-of-the-art genome annotation assessment tools measure the completeness of a gene repertoire, but are blind to other types of errors, such as gene over-prediction or contamination. We developed OMArk, a software relying on fast, alignment-free sequence comparisons between a query proteome and precomputed gene families across the tree of life. OMArk assesses not only the completeness, but also the consistency of the gene repertoire as a whole relative to closely related species. It also reports likely contamination events. We validated OMArk with simulated data, then performed an analysis of the 1805 UniProt Eukaryotic Reference Proteomes, illustrating its usefulness for comparing and prioritizing proteomes based on their quality measures. In particular, we found strong evidence of contamination in 59 proteomes, and identified error propagation in avian gene annotation resulting from the use of a fragmented zebra finch proteome as reference. OMArk is available on GitHub (https://github.com/DessimozLab/OMArk), as a Python package on PyPi, and as an interactive online tool at https://omark.omabrowser.org/.
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