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Topic Review
Free Recall
Free recall is a common task in the psychological study of memory. In this task, participants study a list of items on each trial, and then are prompted to recall the items in any order. Items are usually presented one at a time for a short duration, and can be any of a number of nameable materials, although traditionally, words from a larger set are chosen. The recall period typically lasts a few minutes, and can involve spoken or written recall. The standard test involves the recall period starting immediately after the final list item; this can be referred to as immediate free recall (IFR) to distinguish it from delayed free recall (DFR). In delayed free recall, there is a short distraction period between the final list item and the start of the recall period. Both IFR and DFR have been used to test certain effects that appear during recall tests, such as the primacy effect and recency effect.
  • 1.1K
  • 04 Nov 2022
Topic Review
Maximum Genetic Diversity
Maximum Genetic Diversity (MGD) is a scientific hypothesis relating to molecular evolution, which is the study of how and why populations of organisms experience genetic changes over time. MGD starts with the observation that some regions of the genome are more likely to preserve mutations into the next generation than others. This difference in the observed rate of mutation means some regions of the genome appear to mutate faster than others, and is theorized to relate to balancing the preservation of vital information relating to a species' function against its ability to mutate and adapt to new environmental niches. According to MGD, these regions of the genome eventually drift into two rough categories: faster-mutating sections tuned to respond quickly to environmental pressures and allow adaptive radiation, as well as slower-mutating sections involved in an organism's most fundamental instructions. Because MGD asserts that only slow-mutating genes accurately reflect shared evolutionary history, relationships between species can alternatively be calculated by their "maximum genetic diversity," which is determined by measuring the frequency of mutations in specific corresponding regions of orthologous genes instead of using raw overall genetic similarity. Using calculations based on mutations in these slow-mutating genes provides a chart of genetic ancestry that lines up with the fossil record – measurements based on raw genetic similarity yield results that clash with the fossil record. Also due to this grouping into fast and slow, MGD hypothesizes that over time complex organisms become genetically fragile and less tolerant to mutation as their MGD decreases, since an increasing proportion of their genome will have become slow-mutating over time. MGD asserts that this is because increased organismal and social complexity means more of the genome is needed to preserve the expanding instructional manual necessary for complex behavior and function, and so more of an organism's genome must become slow-mutating as the organism increases in complexity, since being slow-mutating preserves and protects those vital instructions. MGD seeks to reconcile the inconsistencies observed around the neutral theory of molecular evolution, whose "original lines of evidence... are now falsified" according to a paper published in Oxford's Molecular Biology and Evolution in 2018. One example of this is that supposedly consistent and neutral mutation rates from proteins across a wide range of species were demonstrably not neutral nor consistent. Another study published in Nature in December 2019 noted that "defining the evolutionary time scales according to the molecular clock is intrinsically biased, especially for proteins of complex organisms." Although a number of other arguments have been proposed against the neutral theory in recent years, there is not a yet a consensus that the neutral theory is entirely falsified and counter-arguments against the role of selection do exist. Furthermore, beyond the fact that MGD is still relatively unknown, it also contradicts the current paradigm in molecular evolution, since the neutral theory's fundamental premises are still nearly ubiquitously utilized in genetic analysis and admixture studies. Additionally, some of the phenomena explained by MGD could theoretically be accounted for by other processes such as gene conversion or concerted evolution. Lastly, even if the neutral theory is disproved, it does not necessarily validate MGD, as alternative theories have been proposed that also incorporate the effects of selection on the genome. And so MGD will have to be more rigorously tested against any alternative theories before becoming widely adopted. However, to date MGD has not been contradicted in peer-reviewed literature, and its assumptions and framework have been confirmed when it comes to examining the ratio of brain-specific proteins in a range of mammals, for classifying and timing the evolutionary genetic structure of a wide range of organisms ranging from yeast to primates, by evaluating the genetic fitness of yeast which become more genetically fragile as they become more fit, by a genetic model that seeks to more accurately model not only the location of mutations but the rate at which they occur, and by the observation that vital slow-mutating genes are more protected by "transcriptional scanning" in mammalian testes than fast-evolving genes involved with responding quickly to environmental challenges.
  • 1.1K
  • 25 Nov 2022
Topic Review
Chromosome Conformation Signatures
Epigenetic mechanisms mediate the integration of genetic and environmental factors that are responsible for changes in phenotypes. The organisation of the human genome within three-dimensional space (the 3D genome) is a dynamic epigenetic regulator of phenotypic expression. Mediated through the changing spatial proximity of genomic regions relative to one another in 3D space, ‘chromosome conformations’ have emerged in the past several years as a novel class of molecular switches that regulate cellular and physiological processes. Technological advances in the detection of chromosome conformations have spawned a new class of biomarker - the chromosome conformation signature (CCS) - that identifies chromosomal interactions across multiple genomic loci as a collective marker of distinct epigenomic states. The use of CCSs in basic and clinical research has shown recent applications in identifying disease states, subtyping disease states, and prospectively stratifying individuals according to their likely response to medical intervention.
  • 1.1K
  • 19 Aug 2020
Topic Review
Arbuscular Mycorrhizal Fungi and Microbes Interaction
Arbuscular mycorrhizal fungi (AMF) and soil microbe interactions are among the most important and influential processes that occur, as they significantly influence the plant growth and soil structure properties. Their interactions may be of crucial importance to the sustainable, low-input productivity of paddy ecosystems.
  • 1.1K
  • 16 Jun 2022
Topic Review
BARD1 and Tumor Development
BARD1 is a very important BRCA1 binding partner and plays a key role in the development of a variety of tumors. Similar to BRCA1, BARD1 has been implicated in the development of breast and gynecological cancers. In addition, BARD1 also plays a role in the development of non-breast and non-gynecological cancers.
  • 1.1K
  • 30 Jul 2020
Topic Review
Sarcopenia
Sarcopenia, a geriatric disease characterized by a progressive loss of skeletal muscle mass and loss of muscle function, consists of a rising, often undiagnosed health problem.
  • 1.1K
  • 13 Jan 2022
Topic Review
The Honey Bee Apis mellifera
The honey bee Apis mellifera Linnaeus (1758) provides many benefits to humans and ecosystems. This species is an important pollinator in natural environments, which may help to preserve and restore the biodiversity of wild plants. On the other hand, pollination in agro-ecosystems by managed honey bee colonies may enhance crop yield and quality, meeting the increasing food demand. Beekeeping is also a high-valued and income-generating activity, which provides humans with honey as high-quality food as well as substances used as raw materials and in pharmaceuticals. In addition, the honey bee and its products are valuable bioindicators and bioaccumulators of environmental pollution: they provide valuable information on the impact of human activities, enabling the implementation of measures to mitigate risks to human and ecosystem health. The honey bee is also linked to many cultural ecosystem services and has a longstanding tradition in human culture, mysticism, and religion. Its popularity may be therefore used for educational purposes and to raise public awareness of important issues, such as the conservation of pollinator habitats and biodiversity.
  • 1.1K
  • 22 Jun 2022
Topic Review
Plasmopara viticola
Plasmopara viticola, the causal agent of grapevine downy mildew, is a high risk pathogen associated with the development of fungicide resistance.
  • 1.1K
  • 26 Feb 2021
Topic Review
Biological Production of Vanillin
Vanillin (4-hydroxy-3-methoxybenzaldehyde), the primary ingredient in vanilla bean or pod extracts, possesses a rich, creamy, and distinctive vanilla smell, which is also one of the most significant aromas in the world. Vanillin can serve as a flavoring agent in the food industry (about 60%), a pharmaceutical intermediate in the pharmaceutical industry (about 7%), and a scent ingredient in the cosmetics sector (about 33%).
  • 1.1K
  • 08 May 2023
Topic Review
Aptasensors and Aptamers
A kind of biosensor using aptamers as BRE is known as aptasensor. Aptamers are synthetic single-stranded oligonucleotide sequences (RNA or DNA) with high specificity and affinity to bind a variety of target classes including proteins, peptides, drugs, small molecules, whole cells, inorganic and organic molecules, etc.
  • 1.1K
  • 19 Apr 2021
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