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Topic Review
Animal Diet Analysis
Diet analysis is a critical content of animal ecology and the diet analysis methods have been constantly improving and updating. Traditional diet analysis methods include direct observation of foraging behavior, the cafeteria diet, microscopic identification of prey remains in fecal and stomach contents. The molecular-based analysis of animal diets has recently become popular, as they confer high resolution and accuracy, which is mainly achieved through the cloning sequencing or the next generation sequencing (NGS) on the amplification of prey DNA in dietary samples.
  • 1.4K
  • 01 Dec 2021
Topic Review
Bird’s-Eye View of Chromosomic Evolution in Class Aves
Birds (Aves) are the most speciose of terrestrial vertebrates, displaying Class-specific characteristics yet incredible external phenotypic diversity. Critical to agriculture and as model organisms, birds have adapted to many habitats. The only extant examples of dinosaurs, birds emerged ~150 mya and >10% are currently threatened with extinction.
  • 94
  • 28 Feb 2024
Topic Review
Cenancestor
Cenancestor, the last universal cellular ancestor (LUCA), is assumed to exist on the basis of extensive sharing of inferred homologous characters among representatives of living cellular organisms. These characters include the near universal genetic code, the concordance of phylogenetic trees from different genes, the sharing of fundamental biochemical processes and the existence of numerous transitional fossils. A cenancestor is a logical necessity if the cellular structure originated only once, given the cell theory stating that news cells are created by old cells dividing into two. The recent empirical search for the cenancestor started with the prediction that eukaryotes could not possibly have evolved from the common ancestor of extant bacterial species. This led to the discovery of Archaebacteria and the three domains of life. Archaebacteria was found to be "archae" only to eukaryotes and consequently renamed to Archaea. The molecular substantiation of the endosymbiotic hypothesis of mitochondrial and chloroplast origin led to the hypothesis that the nucleus in eukaryotes is also an organelle originating from endosymbiosis or cell fusion, followed by massive horizontal gene transfer (HGT) between an engulfing host and engulfed guests which serve as mitochondrial and chloroplast progenitors. The cenancestor is expected to coexist with a variety of viruses that may mediate HGT to bring heterogeneous genomes together. This virus-mediated and plasmid-mediated genomic assembly and exchange could abolish one major difficulty in creating endosymbiotic genomes, i.e., the need of primitive cells engulfing each other – a difficult feat if they had cell walls.
  • 214
  • 05 Sep 2023
Topic Review
Childhood Socioeconomic Status and Adult Food Preference
Early childhood socioeconomic status (SES) conditions can influence how an adult responds to stress, their food preferences, the volume of food consumed, the likelihood that one will desire to eat in the absence of an energy deficit, the development of eating disorders, and the likelihood that one will suffer from adult obesity.
  • 354
  • 07 Jul 2022
Topic Review
Circum-Saharan Prehistory through the Lens of mtDNA Diversity
African history has been significantly influenced by the Sahara, which has represented a barrier for migrations of all living beings, including humans. Major exceptions were the gene flow events that took place between North African and sub-Saharan populations during the so-called African Humid Periods, especially in the Early Holocene (11.5 to 5.5 thousand years ago), and more recently in connection with trans-Saharan commercial routes. The research indicates that maternal gene flow must have been important in this circum-Saharan space, not only within North Africa and the Sahel/Savannah belt but also between these two regions.
  • 504
  • 25 Mar 2022
Topic Review
Clays and the Origin of Life
Clays are able to replicate and drive the evolution of metabolism; they have the catalytic ability to synthesize monomers (amino acids, nucleotides and so on) and polymerize them, resulting in RNA–peptide worlds in which RNA replicates (genes) and, in cooperation with coded peptides, drives the evolution of the cell. 
  • 1.8K
  • 25 Feb 2022
Topic Review
Cognition-Based Evolution
Cognition-Based Evolution (CBE) asserts a comprehensive alternative approach to phenotypic variation and the generation of biological novelty. In CBE, evolutionary variation is the product of natural cellular engineering that permits purposive genetic adjustments as cellular problem-solving. CBE upholds that the cornerstone of biology is the intelligent measuring cell. Since all biological information that is available to cells is ambiguous, multicellularity arises from the cellular requirement to maximize the validity of available environmental information. This is best accomplished through collective measurement purposed towards maintaining and optimizing individual cellular states of homeorhesis as dynamic flux that sustains cellular equipoise. The collective action of the multicellular measurement and assessment of information and its collaborative communication is natural cellular engineering. Its yield is linked cellular ecologies and mutualized niche constructions that comprise biofilms and holobionts. In this context, biological variation is the product of collective differential assessment of ambiguous environmental cues by networking intelligent cells. Such concerted action is enabled by non-random natural genomic editing in response to epigenetic impacts and environmental stresses. Random genetic activity can be either constrained or deployed as a ‘harnessing of stochasticity’. Therefore, genes are cellular tools. Selection filters cellular solutions to environmental stresses to assure continuous cellular-organismal-environmental complementarity. Since all multicellular eukaryotes are holobionts as vast assemblages of participants of each of the three cellular domains (Prokaryota, Archaea, Eukaryota) and the virome, multicellular variation is necessarily a product of co-engineering among them. 
  • 799
  • 20 May 2021
Topic Review
Dehydrin Genes in Model Brachypodium Grasses
Dehydration proteins (dehydrins, DHNs) confer tolerance to water-stress deficit in plants. We performed a comparative genomics and evolutionary study of DHN genes in four model Brachypodium grass species. Ten dehydrins have been describe within Brachypodium species. Due to limited knowledge on dehydrin expression under water deprivation stress in Brachypodium, we also performed a drought-induced gene expression analysis in 32 ecotypes of the genus’ flagship species B. distachyon showing different hydric requirements. Bdhn1 - Bdhn2, Bdhn3 and Bdhn7 genes, orthologs of wheat, barley, rice, sorghum, and maize genes, were more highly expressed in plants under drought conditions.
  • 483
  • 13 Dec 2021
Topic Review
Development of SARS-CoV-2 Variants
A novel coronavirus (SARS-CoV-2) emerged towards the end of 2019 that caused a severe respiratory disease in humans called COVID-19. It led to a pandemic with a high rate of morbidity and mortality that is ongoing and threatening humankind. Most of the mutations occurring in SARS-CoV-2 are synonymous or deleterious, but a few of them produce improved viral functions. The first known mutation associated with higher transmissibility, D614G, was detected in early 2020. Since then, the virus has evolved; new mutations have occurred, and many variants have been described. Depending on the genes affected and the location of the mutations, they could provide altered infectivity, transmissibility, or immune escape. To date, mutations that cause variations in the SARS-CoV-2 spike protein have been among the most studied because of the protein’s role in the initial virus–cell contact and because it is the most variable region in the virus genome. Some concerning mutations associated with an impact on viral fitness have been described in the Spike protein, such as D614G, N501Y, E484K, K417N/T, L452R, and P681R, among others. To understand the impact of the infectivity and antigenicity of the virus, the mutation landscape of SARS-CoV-2 has been under constant global scrutiny. The virus variants are defined according to their origin, their genetic profile (some characteristic mutations prevalent in the lineage), and the severity of the disease they produce, which determines the level of concern. If they increase fitness, new variants can outcompete others in the population. The Alpha variant was more transmissible than previous versions and quickly spread globally. The Beta and Gamma variants accumulated mutations that partially escape the immune defenses and affect the effectiveness of vaccines. Nowadays, the Delta variant, identified around March 2021, has spread and displaced the other variants, becoming the most concerning of all lineages that have emerged. The Delta variant has a particular genetic profile, bearing unique mutations, such as T478K in the spike protein and M203R in the nucleocapsid. This entry summarizes the current knowledge of the different mutations that have appeared in SARS-CoV-2, mainly on the spike protein. It analyzes their impact on the protein function and, subsequently, on the level of concern of different variants and their importance in the ongoing pandemic. 
  • 755
  • 28 Dec 2021
Topic Review
Dinosaurs
According to Britannica, dinosaurs are described as “Triceratops, contemporary birds, their most recent common ancestor and all of their descendants.” However, for biologists, it could be simpler to picture dinosaurs as reptiles with hind limbs held erect beneath the trunk, similar to how mammals’ hind limbs are held.
  • 872
  • 06 Jan 2023
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