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Mar 2024 DOI 10.14302/issn.2689-4602.jes-24-4982
Mammalian Rbm45 is predominately expressed in neuronal tissue and is integral in brain development and neuronal differentiation under physiological conditions. Dysregulation of Rbm45 has been strongly associated with neurodegenerative disorders in humans and can drive hepatocellular carcinoma through reprogramming lipid metabolism. Intriguingly, Rbm45 is an ancient protein, evolutionarily conserved throughout metazoans, including in sponges which lack a nervous system. Curiously, the evolution of Rbm45 gene structure and protein domain conservation across kingdom Animalia is largely unknown. We performed phylogenetic analysis of Rbm45 nucleotide and amino acid sequences from 36 species representing 9 phyla: Porifera, Cnidaria, Priapulida, Mollusca, Brachiopoda, Arthropoda, Echinodermata, Hemichordata, and Chordata. While the tree from Rbm45 nucleotide sequence data resulted in clades Protostomia and Deuterostomia showing paraphyly, the phylogeny derived from Rbm45 amino acid sequence largely recapitulated known monophyletic relationships among metazoans. Human RBM45 protein structure includes three RNA-binding domains (RBD), a homo-oligomerization association (HOA) domain, a nuclear localization sequence (NLS), and a nuclear export sequence (NES). Multiple sequence alignment across the same 36 taxa used for phylogenetic analysis revealed conservation of all three RBDs, the HOA, and NLS; in contrast the NES was only detected in clade Craniata and not in clades Ambulacraria and Protostomia. Rbm45 gene structure analysis revealed increasing gene complexity concomitant with increasing evolutionary complexity. Rbm45 from non-bilaterian taxa had from 2 to 4 large exons, while bilaterian taxa had between 6 to17 small exons. These findings demonstrate that Rbm45 is an ancient, highly conserved gene among metazoans suggesting a function in a breadth of neural/sensory systems.
Mar 2021 DOI 10.14302/issn.2692-1537.ijcv-21-3756
In contributing to the initiative to address the COVID-19 pandemic and in order to enhance the knowledge on driving forces shaping the evolution of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) (isolated from Tunisian patients), a comparison in relation to other coronaviruses infecting humans (SARS-CoV-1, MERS-CoV, HCoV/229E, HCoV/NL63, HCoV/OC43, and HCoV/HKU1) as well as animals (SARS-CoVs in tiger, bats, civet, pangolin, bovine, and MERS-CoV in dromedary/camel), was conducted. In-depth analysis was carried out involving 115 sequences of spike glycoprotein-coding gene extracted from the international databases. Phylogeny inference allowed the reconstruction of a bifurcating tree where four distinct groups were delineated and at the same time, three animal accessions (SARS-CoV-2/tiger, MERS-CoV/camel, and SARS-CoV/bovine) shifted from the animal group and integrated the human coronaviruses clades. Nonetheless, in the presence of reticulate events such as recombination, networks described better the phylogenetic relationships rather than the classic dendrogram. Thus, networks were produced and identified four clusters containing sharply demarcated subgroups (eight subdivisions). Except networked phylogenies of SARS-CoV-1, SARS-CoV-2, and HCoV/HKU1, all the others showed edges and boxes illustrating the occurrence of incompatibilities related to the sequences of spike glycoprotein-coding gene. Thereby and consolidating this result, three methods (RDP package, GARD, and RECCO) were used to detect breakpoints in aligned sequences. Except the clades SARS-CoV-1 and SARS-CoV-2, all the remaining phylogenetic subdivisions were subject to recombination. Furthermore, the screening of selection pressure in all studied sequences by various statistics-based models of the HyPhy package, showed that, similarly, the lineages belonging to the clades SARS-CoV-1 and SARS-CoV-2 were not under selection. In contrast, all members of the remaining clades underwent, to different extents, adaptive selection as well as purifying selection.
Apr 2018
This essay argues for integrating evolutionary and functional perspectives in bird studies within converted habitats. It highlights how behavior, morphology, and phylogeny interact under land‑use change.
Feb 2016 DOI 10.14302/issn.2575-7881.jdrr-15-849
Reverse Transcription Polymerase Chain Reaction (RT-PCR) using new designed primers pair for Heat Shock Protein70 homologue (HSP70h) of Olive leaf yellowing-associated virus revealed 667 amplified product of 10 olive accessions collected from various olive-growing regions in Tunisia. Amplicons were cloned and sequenced. The sequences were deposited in the international databases. Pairwise sequence comparisons among 10 Tunisian isolates along with a reference sequence (AJ440010) extracted from GenBank revealed a nucleotide identity of 86.06-99.40 and an amino acid similarity of 91.89-99.55. Sequence multiple alignments were searched for evidence of recombination using three methods, ie. Differences of Sums of Squares (DSS) implemented in TOPALi v2.5 software and Single Breakpoint (SBP) along with GARD, a genetic algorithm, both incorporated in HyPhy package. All used methods pointed out the presence of putative breaking points in partially sequenced HSP70h-coding gene. Since failing to account for recombination can mislead the phylogeny inference and can elevate the false positive error rate in positive selection assessment, the use of GARD resulted in the reconstruction of different phylogenies on the left as well as on the right sides of putative recombination breaking points, and the 11 accessions were distributed into at least three clusters compared to MEGA6 software which delineated only two clades. Nonetheless, by dividing the aligned sequences at breakpoints into separate sequence sets, MEGA6 delineated a clustering pattern different from the former two. As a result, recombination reshuffled the affiliation of the different accessions to the clusters. Analysis of selection pressures exerted on HSP70h encoded protein using different models (SLAC, IFEL, FEL, REL, PARRIS, FUBAR, MEME, GA Branch, and PRIME) taking into account recombination, and implemented in HyPhy package, revealed that it underwent predominantly purifying selection as confirmed by Tajima’s D, Fu and Li’s D and F tests, and SNAP algorithm. However, a few sites were also under positive selection as assessed by various models such as FEL, IFEL, REL, MEME, and PRIME.