scholarly journals Ionotropic Receptors as a Driving Force behind Human Synapse Establishment

2020 ◽  
Author(s):  
Lucas Henriques Viscardi ◽  
Danilo Oliveira Imparato ◽  
Maria Cátira Bortolini ◽  
Rodrigo Juliani Siqueira Dalmolin
Keyword(s):  
Driving Force ◽  
Gene Network ◽  
Common Ancestor ◽  
Synaptic Proteins ◽  
Main Theme ◽  
Ionotropic Receptors ◽  
Nervous Systems ◽  
Evolutionary Scenario ◽  
Human Genes ◽  
Synaptic Neurotransmission

Abstract The origin of nervous systems is a main theme in biology and its mechanisms are largely underlied by synaptic neurotransmission. One problem to explain synapse establishment is that synaptic orthologs are present in multiple aneural organisms. We questioned how the interactions among these elements evolved and to what extent it relates to our understanding of the nervous systems complexity. We identified the human neurotransmission gene network based on genes present in GABAergic, glutamatergic, serotonergic, dopaminergic, and cholinergic systems. The network comprises 321 human genes, 83 of which act exclusively in the nervous system. We reconstructed the evolutionary scenario of synapse emergence by looking for synaptic orthologs in 476 eukaryotes. The Human–Cnidaria common ancestor displayed a massive emergence of neuroexclusive genes, mainly ionotropic receptors, which might have been crucial to the evolution of synapses. Very few synaptic genes had their origin after the Human–Cnidaria common ancestor. We also identified a higher abundance of synaptic proteins in vertebrates, which suggests an increase in the synaptic network complexity of those organisms.

Mouse Hox-3.4: homeobox sequence and embryonic expression patterns compared with other members of the Hox gene network

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 329-339 ◽  
Author(s):  
S.J. Gaunt ◽  
P.L. Coletta ◽  
D. Pravtcheva ◽  
P.T. Sharpe
Keyword(s):  
Gene Network ◽  
Common Ancestor ◽  
Expression Patterns ◽  
Homeobox Gene ◽  
Predicted Amino Acid Sequence ◽  
Chromosome 15 ◽  
Hox Gene ◽  
The Central Nervous System ◽  
Genomic Organisation

A putative mouse homeobox gene (Hox-3.4) was previously identified 4kb downstream of the Hox-3.3 (Hox-6.1)* gene (Sharpe et al. 1988). We have now sequenced the Hox-3.4 homeobox region. The predicted amino acid sequence shows highest degree of homology in the mouse with Hox-1.3 and -2.1. This, together with similarities in the genomic organisation around these three genes, suggests that they are comembers of a subfamily, derived from a common ancestor. Hox-3.4 appears to be a homologue of the Xenopus Xlhbox5 and human cp11 genes (Fritz and De Robertis, 1988; Simeone et al. 1988). Using a panel of mouse-hamster somatic cell hybrids we have mapped the Hox-3.4 gene to chromosome 15. From the results of in situ hybridization experiments, we describe the distribution of Hox-3.4 transcripts within the 12 1/2 day mouse embryo, and we compare this with the distributions of transcripts shown by seven other members of the Hox gene network. We note three consistencies that underlie the patterns of expression shown by Hox-3.4. First, the anterior limits of Hox-3.4 transcripts in the embryo are related to the position of the Hox-3.4 gene within the Hox-3 locus. Second, the anterior limits of Hox-3.4 expression within the central nervous system are similar to those shown by subfamily homologues Hox-2.1 and Hox-1.3, although the tissue-specific patterns of expression for these three genes show many differences. Third, the patterns of Hox-3.4 expression within the spinal cord and the testis are very similar to those shown by a neighbouring Hox-3 gene (Hox-3.3), but they are quite different from those shown by Hox-1 genes (Hox-1.2, -1.3 and -1.4).

scholarly journals The evolution and diversity of the nonsense-mediated mRNA decay pathway

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1299 ◽  
Author(s):  
James P. B. Lloyd
Keyword(s):  
Alternative Splicing ◽  
Stress Response ◽  
Driving Force ◽  
Mrna Decay ◽  
Common Ancestor ◽  
Last Eukaryotic Common Ancestor ◽  
Eukaryotic Evolution ◽  
Premature Termination Codons ◽  
Upstream Orf ◽  
Nonsense Mediated Mrna Decay

Nonsense-mediated mRNA decay is a eukaryotic pathway that degrades transcripts with premature termination codons (PTCs). In most eukaryotes, thousands of transcripts are degraded by NMD, including many important regulators of development and stress response pathways. Transcripts can be targeted to NMD by the presence of an upstream ORF or by introduction of a PTC through alternative splicing. Many factors involved in the recognition of PTCs and the destruction of NMD targets have been characterized. While some are highly conserved, others have been repeatedly lost in eukaryotic lineages. Here, I outline the factors involved in NMD, our current understanding of their interactions and how they have evolved. I outline a classification system to describe NMD pathways based on the presence/absence of key NMD factors. These types of NMD pathways exist in multiple different lineages, indicating the plasticity of the NMD pathway through recurrent losses of NMD factors during eukaryotic evolution. By classifying the NMD pathways in this way, gaps in our understanding are revealed, even within well studied organisms. Finally, I discuss the likely driving force behind the origins of the NMD pathway before the appearance of the last eukaryotic common ancestor: transposable element expansion and the consequential origin of introns.

scholarly journals Phylostratigraphic Analysis Shows the Earliest Origination of the Stress Associated Genes in A. thaliana

2018 ◽  
Author(s):  
Zakhar Mustafin ◽  
Dmitry Konstantinov ◽  
Vladimir Zamyatin ◽  
Alexey Doroshkov ◽  
Sergey Lashin ◽  
...  
Keyword(s):  
Heat Stress ◽  
Gene Networks ◽  
Gene Network ◽  
Common Ancestor ◽  
Cold Water ◽  
Light Stress ◽  
Graphical Analysis ◽  
Last Common Ancestor ◽  
Molecular Processes ◽  
Different Response

Phylostratigraphic analysis is a way to look anew on phylogenetic data in the evolutionary aspect. It allows counting the evolutionary age based on the analysis of genes, their orthologs and finding the last common ancestor. We performed phylostratigraphic analysis of Arabidopsis thaliana genes associated with several types of abiotic stresses (heat, cold, water-related, light, osmotic, salt, and oxidative) determined by the Gene Ontology annotation. Comparison of the distributions of ages of genes associated with stresses of different type has shown the heat stress to involve older genes while the light stress – younger genes. At the same time, all types of stress are characterized by a significantly higher proportion of old genes (common to all eukaryotes) compared to the whole set of A.thaliana genes. This can be explained by the involvement of basic molecular processes in plant cells into the stress response. Reconstruction and graphical analysis of the gene network of the heat stress educed several clusters associated with different response functions. Some of these clusters contain only ancient genes. The results obtained show that the phylostratigraphic analysis reveals the fundamental features of the organization of gene networks and their evolution.

scholarly journals Ecological opportunity as a driving force for radiation events and time-dependent evolutionary rates in papillomaviruses

2020 ◽  
Author(s):  
Anouk Willemsen ◽  
Ignacio G. Bravo
Keyword(s):  
Driving Force ◽  
Evolutionary History ◽  
Evolutionary Rates ◽  
Molecular Dating ◽  
Time Dependent ◽  
Ecological Opportunity ◽  
Dependent Rate ◽  
Evolutionary Scenario ◽  
Speciation Rates ◽  
History Of

AbstractPapillomaviruses (PVs) have a wide host range, infecting mammals, birds, turtles, and snakes. The recent discovery of PVs in different fish species allows for a more complete reconstruction of the evolutionary history of the viral family. In this study we perform phylogenetic dating to analyse evolutionary events that occurred during PV evolution, as well as to estimate speciation and evolutionary rates.We have used four different data sets to explore and correct for potential biases that particular taxa combinations may introduce during molecular time inference. When considering the evolution of substitution rates we observed that short-term rate estimates are much higher than long-term rate estimates, also known as the time-dependent rate phenomenon. We discuss that for PVs the time-dependent evolutionary rates may reflect changes in the available host niches. When considering the evolution of viral branching events (as a proxy for speciation rates), we show that these are not constant through time, suggesting the occurrence of distinct evolutionary events such as adaptive radiations. In a joint analysis with host speciation rates, we identify at least four different evolutionary periods, demonstrating that the evolution of PVs is multiphasic, and refining the previously suggested biphasic evolutionary scenario.Thanks to the discovery of novel PVs in basal hosts and to the implementation of a time-dependent rate model for molecular dating, our results provide new insights into the evolutionary history of PVs. In this updated evolutionary scenario, ecological opportunity appears as one main driving force for the different radiation and key-innovation events we observe.

Brains Through Time

2019 ◽  
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
Animal Behavior ◽  
Common Ancestor ◽  
Functional Organization ◽  
Brain Size ◽  
Brain Regions ◽  
Nervous Systems ◽  
Evolutionary Changes ◽  
Organ Systems ◽  
Cast Doubt ◽  
Ecological Success

Much is conserved in vertebrate evolution, but significant changes in the nervous system occurred at the origin of vertebrates and in most of the major vertebrate lineages. This book examines these innovations and relates them to evolutionary changes in other organ systems, animal behavior, and ecological conditions at the time. The resulting perspective clarifies what makes the major vertebrate lineages unique and helps explain their varying degrees of ecological success. One of the book’s major conclusions is that vertebrate nervous systems are more diverse than commonly assumed, at least among neurobiologists. Examples of important innovations include not only the emergence of novel brain regions, such as the cerebellum and neocortex, but also major changes in neuronal circuitry and functional organization. A second major conclusion is that many of the apparent similarities in vertebrate nervous systems resulted from convergent evolution, rather than inheritance from a common ancestor. For example, brain size and complexity increased numerous times, in many vertebrate lineages. In conjunction with these changes, olfactory inputs to the telencephalic pallium were reduced in several different lineages, and this reduction was associated with the emergence of pallial regions that process non-olfactory sensory inputs. These conclusions cast doubt on the widely held assumption that all vertebrate nervous systems are built according to a single, common plan. Instead, the book encourages readers to view both species similarities and differences as fundamental to a comprehensive understanding of nervous systems.

Manual deixis in apes and humans

2005 ◽  
Vol 5 (3) ◽  
pp. 387-408 ◽  
Author(s):  
David A. Leavens
Keyword(s):  
Common Ancestor ◽  
Great Apes ◽  
Operational Definition ◽  
Cognitive Capacity ◽  
Last Common Ancestor ◽  
Natural Habitats ◽  
Intentional Communication ◽  
Evolutionary Scenario ◽  
In Captivity ◽  
Definition Of

Pointing by apes is near-ubiquitous in captivity, yet rare in their natural habitats. This has implications for understanding both the ontogeny and heritability of pointing, conceived as a behavioral phenotype. The data suggest that the cognitive capacity for manual deixis was possessed by the last common ancestor of humans and the great apes. In this review, nonverbal reference is distinguished from symbolic reference. An operational definition of intentional communication is delineated, citing published or forthcoming examples for each of the defining criteria from studies of manual gestures in apes. Claims that chimpanzees do not point amongst themselves or do not gesture declaratively are refuted with published examples. Links between pointing and cognitive milestones in other domains relating means to ends are discussed. Finally, an evolutionary scenario of pointing as an adaptation to changes in hominid development is briefly sketched.

scholarly journals Nervous systems and scenarios for the invertebrate-to-vertebrate transition

2016 ◽  
Vol 371 (1685) ◽  
pp. 20150047 ◽  
Author(s):  
Nicholas D. Holland
Keyword(s):  
Nervous System ◽  
Gene Network ◽  
Homo Sapiens ◽  
Structural Features ◽  
Central Position ◽  
Network Data ◽  
Comparative Biology ◽  
Functional Importance ◽  
Nervous Systems ◽  
Fossil Data

Older evolutionary scenarios for the origin of vertebrates often gave nervous systems top billing in accordance with the notion that a big-brained Homo sapiens crowned a tree of life shaped mainly by progressive evolution. Now, however, tree thinking positions all extant organisms equidistant from the tree's root, and molecular phylogenies indicate that regressive evolution is more common than previously suspected. Even so, contemporary theories of vertebrate origin still focus on the nervous system because of its functional importance, its richness in characters for comparative biology, and its central position in the two currently prominent scenarios for the invertebrate-to-vertebrate transition, which grew out of the markedly neurocentric annelid and enteropneust theories of the nineteenth century. Both these scenarios compare phyla with diverse overall body plans. This diversity, exacerbated by the scarcity of relevant fossil data, makes it challenging to establish plausible homologies between component parts (e.g. nervous system regions). In addition, our current understanding of the relation between genotype and phenotype is too preliminary to permit us to convert gene network data into structural features in any simple way. These issues are discussed here with special reference to the evolution of nervous systems during proposed transitions from invertebrates to vertebrates.

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