Recombination is a crucial process in the evolution of many organisms. Although the evolutionary reasons behind its occurrence in RNA viruses are debated, this phenomenon has been associated with major epidemiological events such as virus host range expansion, antigenic shift or variation in virulence 1,2, and this process occurs frequently in positive strand RNA viruses such as coronaviruses. The SARS-CoV-2 pandemic has been associated with the repeated emergence of variants of concern presenting increased transmissibility, severity or immune escape 3. The recent extensive circulation of Delta worldwide and its subsequent replacement by viruses of the Omicron lineage 4 (BA.1 then BA.2), have created conditions for genetic exchanges between viruses with both genetic diversity and phenotypic specificities 5-7. Here we report the identification and in vitro and in vivo characterization of a Delta-Omicron recombinant in Europe. This recombinant exhibits immune escape properties similar to Omicron, while its behavior in mice expressing the human ACE2 receptor is more similar to Delta. This recombinant provides a unique and natural opportunity to better understand the genotype to phenotype links in SARS-CoV-2.
Native plants in extreme environments may harbor some unique microbial communities with particular functions to sustain their growth and tolerance to harsh conditions. The aim of this study was to investigate the bacterial communities profiles in some native plants and samples of the Moroccan phosphate mine ecosystem by assessing the percentages of taxonomic identification using six hypervariable regions of the 16S rRNA. The rhizosphere of the three wild plants in the Moroccan phosphate mine is characterized by interesting bacterial diversity including Proteobacteria (62.24%, 71.15% and 65.61%), Actinobacteria (22.53%, 15.24%, 22.30%), Bacteroidetes (7.57%; 4.23%; 7.63%), and Firmicutes (5.82%; 1.17%; 2.83%). The bulk phosphate mine samples were dominated by Actinobacteria with average relative abundance of 97.73% that are different from those inferred in the rhizosphere samples of the native plants. The regions V3, V4 and V67 performed better in the taxonomic profiling at different taxonomic levels. Results indicated that both plant genotype and mainly soil conditions may be involved in the shaping of bacterial diversity. Such indication was also confirmed by the prediction of functional profiles that showed enrichment of many functions related to biological nitrogen fixation in the rhizosphere of native plants and the stress related functions in the bulk phosphate mine in comparison with the wheat rhizosphere samples.
Background
Epilepsy is the most common neurological disorder that causes spontaneous, unprovoked, and recurrent seizures. Epilepsy is clinically and genetically heterogeneous with various modes of inheritance. The complexity of epilepsy presents a challenge and identification of the causal genetic mutation allows diagnosis, genetic counseling, predicting prognosis, and, in some cases, treatment decisions. Clinical exome sequencing is actually becoming a powerful approach for molecular diagnosis of heterogeneous neurological disorders in clinical practice.
Case presentation
We report our observations of three unrelated Moroccan patients referred to our genetics department for molecular diagnosis of epilepsy: a 4-year-old Moroccan boy, a 3-year-old Moroccan girl, and a 7-year-old Moroccan boy. Due to the heterogeneity and complexity of epilepsy, we performed clinical exome sequencing followed by targeted analysis of 936 epilepsy genes. A total of three mutations were identified in known epilepsy genes (
SCN1A, SCN2A
). By clinical exome sequencing, we identified two novel mutations: c.4973C>A (p.Thr1658Lys) in
SCN1A
gene and c.1283A>G (p.Tyr428Cys) in the
SCN2A
gene, whereas the third mutation c.3295G>T (p.Glu1099*) was already described in patients with Dravet syndrome.
Conclusion
This study demonstrates that clinical exome sequencing is an effective diagnosis tool to investigate this group of diseases with huge diversity and defends its use in clinical routine.
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