scholarly journals Origin of DNA Repair in the RNA World

2020 ◽  
Author(s):  
Harris Bernstein ◽  
Carol Bernstein

The early history of life on Earth likely included a stage in which life existed as self-replicating protocells with single-stranded RNA (ssRNA) genomes. In this RNA world, genome damage from a variety of sources (spontaneous hydrolysis, UV, etc.) would have been a problem for survival. Selection pressure for dealing with genome damage would have led to adaptive strategies for mitigating the damage. In today’s world, RNA viruses with ssRNA genomes are common, and these viruses similarly need to cope with genome damage. Thus ssRNA viruses can serve as models for understanding the early evolution of genome repair. As the ssRNA protocells in the early RNA world evolved, the RNA genome likely gave rise, through a series of evolutionary stages, to the double-stranded DNA (dsDNA) genome. In ssRNA to dsDNA evolution, genome repair processes also likely evolved to accommodate this transition. Some of the basic features of ssRNA genome repair appear to have been retained in descendants with dsDNA genomes. In particular, a type of strand-switching recombination occurs when ssRNA replication is blocked by a damage in the template strand. Elements of this process appear to have a central role in recombinational repair processes during meiosis and mitosis of descendant dsDNA organisms.

Author(s):  
Erin Lambert

This conclusion offers a brief commentary on the implications of song, resurrection, and belief for the broader history of the Reformation. It relates the various uses of song by Lutherans (hymn pamphlets), Anabaptists (martyr songs), Dutch Reformed exiles (psalms), and Catholics (motets) to these confessions’ ideas of belief as it concerned resurrection and their understandings of how belief was bound up with the Christian life on earth. In place of a story of the transformation of one conception of Christianity to many different conceptions, this book as a whole suggests that the Reformation might be reconceived as a much more elemental debate about the role that belief was to play in a Christian life.


Author(s):  
Lyle K. Grant ◽  
Robert E. Spencer

<P class=abstract>The present paper (a) outlines the basic features of the Personalized System of Instruction (PSI); (b) provides a brief history of PSI; and (c) describes the application of PSI to distance education. Some common misconceptions about PSI are also addressed. PSI is presented as a helpful universally applicable set of instructional practices that are well suited to distance teaching and learning.</P> <P class=abstract><B>Key Terms:</B> Personalized System of Instruction, distance learning, computer-based instruction, mastery-learning, self-pacing, higher-order objectives, scholarship of teaching, proctors, tutoring.</P> <p>


2016 ◽  
Vol 16 (1) ◽  
pp. 40-59 ◽  
Author(s):  
Claudio Maccone

AbstractIn two recent papers (Maccone 2013, 2014) as well as in the book (Maccone 2012), this author described the Evolution of life on Earth over the last 3.5 billion years as a lognormal stochastic process in the increasing number of living Species. In (Maccone 2012, 2013), the process used was ‘Geometric Brownian Motion’ (GBM), largely used in Financial Mathematics (Black-Sholes models). The GBM mean value, also called ‘the trend’, always is an exponential in time and this fact corresponds to the so-called ‘Malthusian growth’ typical of population genetics. In (Maccone 2014), the author made an important generalization of his theory by extending it to lognormal stochastic processes having an arbitrary trend mL(t), rather than just a simple exponential trend as the GBM have.The author named ‘Evo-SETI’ (Evolution and SETI) his theory inasmuch as it may be used not only to describe the full evolution of life on Earth from RNA to modern human societies, but also the possible evolution of life on exoplanets, thus leading to SETI, the current Search for ExtraTerrestrial Intelligence. In the Evo-SETI Theory, the life of a living being (let it be a cell or an animal or a human or a Civilization of humans or even an ET Civilization) is represented by a b-lognormal, i.e. a lognormal probability density function starting at a precise instant b (‘birth’) then increasing up to a peak-time p, then decreasing to a senility-time s (the descending inflexion point) and then continuing as a straight line down to the death-time d (‘finite b-lognormal’).(1)Having so said, the present paper describes the further mathematical advances made by this author in 2014–2015, and is divided in two halves: Part One, devoted to new mathematical results about the History of Civilizations as b-lognormals, and(2)Part Two, about the applications of the Evo-SETI Theory to the Molecular Clock, well known to evolutionary geneticists since 50 years: the idea is that our EvoEntropy grows linearly in time just as the molecular clock. (a)Summarizing the new results contained in this paper: In Part One, we start from the History Formulae already given in (Maccone 2012, 2013) and improve them by showing that it is possible to determine the b-lognormal not only by assigning its birth, senility and death, but rather by assigning birth, peak and death (BPD Theorem: no assigned senility). This is precisely what usually happens in History, when the life of a VIP is summarized by giving birth time, death time, and the date of the peak of activity in between them, from which the senility may then be calculated (approximately only, not exactly). One might even conceive a b-scalene (triangle) probability density just centred on these three points (b, p, d) and we derive the relevant equations. As for the uniform distribution between birth and death only, that is clearly the minimal description of someone's life, we compare it with both the b-lognormal and the b-scalene by comparing the Shannon Entropy of each, which is the measure of how much information each of them conveys. Finally we prove that the Central Limit Theorem (CLT) of Statistics becomes a new ‘E-Pluribus-Unum’ Theorem of the Evo-SETI Theory, giving formulae by which it is possible to find the b-lognormal of the History of a Civilization C if the lives of its Citizens Ci are known, even if only in the form of birth and death for the vast majority of the Citizens.(b)In Part Two, we firstly prove the crucial Peak-Locus Theorem for any given trend mL(t) and not just for the GBM exponential. Then we show that the resulting Evo-Entropy grows exactly linearly in time if the trend is the exponential GMB trend.(c)In addition, three Appendixes (online) with all the relevant mathematical proofs are attached to this paper. They are written in the Maxima language, and Maxima is a symbolic manipulator that may be downloaded for free from the web.In conclusion, this paper further increases the huge mathematical spectrum of applications of the Evo-SETI Theory to prepare Humans for the first Contact with an Extra-Terrestrial Civilization.


2019 ◽  
Vol 12 (2) ◽  
pp. 511-526
Author(s):  
D. V. Mukhetdinov

The article deals with the history of development and basic ideas of Islamic feminist hermeneutics. In order to understand tendencies of development of the modern Islamic thought, it is important as well to study feminist ideas in their complexity. The author argues that feminist hermeneutics in Islam represents a set of approaches towards the interpretation of the Holy Qur’an, the Hadith and secondary sources of Islamic spiritual tradition. In the typological perspective, it is close to the so-called “Standpoint feminism”. The author singles out seven basic features to Islamic feminist hermeneutics, which are the religious frame of mind, following the principles of Islamic ethics, the use of so-called “contextual ijtihad”, accepting the egalitarist values, the critical approach to tradition, the critical approach towards the Hadith, use of the new methodology, which has its roots in the heritage of Neomodernist school of thought.


1996 ◽  
Vol 70 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Desmond Collins

The remarkable “evolution” of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of “a hitherto unknown phylum.”Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.


2012 ◽  
Vol 11 (4) ◽  
pp. 345-350 ◽  
Author(s):  
Marcelo Gleiser

AbstractThe history of life on Earth and in other potential life-bearing planetary platforms is deeply linked to the history of the Universe. Since life, as we know, relies on chemical elements forged in dying heavy stars, the Universe needs to be old enough for stars to form and evolve. The current cosmological theory indicates that the Universe is 13.7 ± 0.13 billion years old and that the first stars formed hundreds of millions of years after the Big Bang. At least some stars formed with stable planetary systems wherein a set of biochemical reactions leading to life could have taken place. In this paper, I argue that we can divide cosmological history into four ages, from the Big Bang to intelligent life. The physical age describes the origin of the Universe, of matter, of cosmic nucleosynthesis, as well as the formation of the first stars and Galaxies. The chemical age began when heavy stars provided the raw ingredients for life through stellar nucleosynthesis and describes how heavier chemical elements collected in nascent planets and Moons gave rise to prebiotic biomolecules. The biological age describes the origin of early life, its evolution through Darwinian natural selection and the emergence of complex multicellular life forms. Finally, the cognitive age describes how complex life evolved into intelligent life capable of self-awareness and of developing technology through the directed manipulation of energy and materials. I conclude discussing whether we are the rule or the exception.


2021 ◽  
Vol 1 (2) ◽  
pp. 80-87
Author(s):  
Toji Omonovich Norov ◽  

The universe, the space that make up their basis planets in it, their creation, the main essence of their creation, form, composition, meaning, movements, interactions, their influence on human life and activities, the role of man in the universe and in life on Earth, life, the criteria of activity and processes occurring in time and space have long been of interest to humanity. One of the main problems in the history of philosophy is the question of space and time. This problem was defined in different ways in the great schools of thought by thinkers of different periods. One of these great thinkers is Alisher Navoi. Navoi's works, along with other socio-philosophical themes, uniquely express and analyze the problems of the firmament and time. Its main feature is that it is based on the divine (pantheistic) religion, Islam, its holy book, the Koran and other theological sources, as well as on the secrets of nature and the Universe, the main miracle of Allah - human intelligence, the power of enlightenment, they are the key revealing all these secrets.


Author(s):  
Muriel Gargaud ◽  
Francis Albarède ◽  
Nicholas Arndt ◽  
Carlos Briones ◽  
Henderson James Cleaves ◽  
...  
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