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Dec 2019 DOI 10.14302/issn.2694-1198.jge-19-3079
Volobuev A.N.Corresponding author
Samara State Medical University, Department of Medical Physics, Samara, Russia
The problem of natural selection against recessive homozygotes in a population is investigated. It is shown that natural selection of mutant alleles linked with the Х-chromosome in a population at women is described by the nonlinear differential equation of the third order. The order of the differential equation characterizes a power of selection. It is marked that the high order of the differential equation of natural selection allows level all mutational processes in Earth populations.
Jun 2018 DOI 10.14302/issn.2689-4602.jes-18-2128
I. Granovitch AndreyCorresponding author
Department of Invertebrate Zoology, Faculty of Biology, St. Petersburg State University
Natural selection is a buzzword used to describe the main driving force of evolution. Its creative role is believed to be based on: a) an unlimited variety of organisms caused by hereditary variation and b) a direct connection between hereditary changes and their phenotypic expression. These are the two requirements that can lead to the genetically based changing modalities of characters through “iterations” of natural selection in the series of successive generations. Are these two requirements fulfilled in the nature, however? The present study focuses on the analysis of these two “foundation stones” of natural selection. Firstly, hereditary variation is shown to be essentially non-homogenous. New hereditary characteristics of individuals fall onto a narrow “strip of land” in the sea of potential possibilities. Secondly, the consequences of changes in the genotype of an organism are involved into a system of hierarchical multiple compensation, from the molecular to the biocenotic level. In a way, the signal of hereditary change passes through a series of “system filters” at epigenetic, ontogenetic, physiological, behavioural, populational and biocenotic level. Each filter is represented by multiple feedbacks maintaining the integrity of systems at each level and at all the hierarchical levels taken together. It is in these “system filters” the adaptive nature of characters is formed representing the every individual as a subject to the Law of Multilevel Self-Organization. The emerging understanding of this provides a strong reason to change the evolutionary paradigm from the mainly selectogenetic to the mainly orthogenetic one.
Mar 2020 DOI 10.14302/issn.2694-1198.jge-20-3206
Volobuev A.N.Corresponding author
Samara State Medical University. Department of Medical Physics. Samara, Russia
On the basis of Hardy – Weinberg’s law the problem of inbreeding in a family tree and a population was investigated. With use of an inbreeding factor are received the discrete equation for a family tree and differential equation for a population. The numerical solution of the differential equation for a population was found and analyzed at various values of the inbreeding factor. Migration of inbred population is investigated in view of natural selection. It was shown that velocity of migration falls with increase of the inbreeding factor. Interrelation of the recessive allele frequency at woman for a migrating population with inbreeding factor and standard parameter of selection was found.
Jan 2020 DOI 10.14302/issn.2694-1198.jge-19-3141
Volobuev A.N.Corresponding author
Samara State Medical University. Department of Medical Physics. Samara, Russia
On the basis of Hardy – Weinberg law the problem of migration from the genetic point of view is considered. It is proved the linear differential equation of migratory process of a panmictic population. The phase of the solution of this equation is investigated. On the basis of the carried out analysis the dependence of migration velocity of a population on average time of alternation of generations is found. It is shown that migration of primitive people from Africa to Europe needed alternation the several hundred generations. The dependence of migration velocity of a population on the average area developed by a population for year is investigated. Lacks of the carried out analysis owing to absence of the account of natural selection and inbreeding are marked.
Sep 2019 DOI 10.14302/issn.2689-4602.jes-19-2990
Shkliarevsky GennadyCorresponding author
Bard College
There is hardly anything more central to our universe than conservation. Many scientific fields and disciplines view the law of conservation as one of the most fundamental universal laws. The Darwinian model pivots the process of evolution on variability, reproduction, and natural selection. Conservation plays a marginal role in this model and is not really universal, as the model allows exceptions to conservation, i.e. non-conservation, to play an equally important role in evolution. This anomalous role of conservation in the Darwinian model raises questions: What is the reason for this anomaly? Is conservation really universal, as we tend to believe or is it not, as the Darwinian model suggests? This contribution proposes a new model of evolution that focuses on levels of organization, rather than of species, organisms, or populations. It argues that conservation is central to evolution. Not only does this new model restores the universal status of conservation but it also makes possible to resolve some outstanding problems and controversies that continue to plague the Darwinian model. The article tries to advance the broad Darwinian project that seeks to explain the process of evolution as a product of the spontaneous processes in nature.
Aug 2019 DOI 10.14302/issn.2572-3030.jcgb-19-2597
Oluwafemi Oyamakin S.Corresponding author
Department of Statistics, University of Ibadan, Nigeria
In other to present a series of stochastic models from population dynamics capable of describing rudimentary aspects of genetic evolution, we studied two-allele Wright–Fisher and the Moran models for evolution of the relative frequencies of two alleles at a diploid locus under random genetic drift in a population of fixed size “simplest form, selection, and random mutation”. Principal results were presented in qualitative terms, illustrated by Monte Carlo simulations from R and http://www.radford.edu/~rsheehy/Gen_flash/popgen. Moran and the Wright-Fisher Models exhibited the same fixation probabilities, only that the Moran model runs twice as fast as the Wright-Fisher Model. A clue that can help us to understand this result is provided by the variance in reproductive success in the two models. Genetic changes due to drift were neither directional nor predictable in any deterministic way. Nonetheless, genetic drift led to evolutionary change in the absence of mutation (P=0.5), natural selection or gene flow. In general, alleles drift to fixation is significantly faster in smaller populations. Probability of fixation of an allele A was approximately equivalent to the initial frequency of that allele. With the inclusion of selection in our model, probability of fixation of a favoured allele due to natural selection increased with increase in fitness advantage and population size. The time taken to reach fixation is much slower, in case of no selective advantage, than a fixation under mutation with selective advantage.
Nov 2017 DOI 10.14302/issn.2576-6694.jbbs-17-1748
Nair AjayCorresponding author
Oklahoma Medical Research Foundation, Arthritis and Clinical Immunology Research Program, Oklahoma City, Oklahoma 73104, USA
Neo-Darwinian natural selection theory indicates that sudden, drastic changes in the environment place selective pressure on genetic variants in a population. As time progresses, this pressure sculpts individuals to better fit this new environment. Waddington’s classic experiment was repeated using white-eyed (the w1118strains) flies which produced the crossveinless (cve; disturbed wing crossveins) trait from the parent generation. The F1 generation was split into two selection lines: an Upward Selection Line, that produced more cve in successive generations, and a Downward Selection Line that responded with a consistent but non-linear decline in the percentage of crossveinless. This article will introduce and enlarge observations made on flies with cve; especially the manner in which the Waddington experiment impacts the population. It seems that Waddington evaluated crossveinless just by what it is good for, but not by the price of using it. That is to say, there is an inevitable cost that needs to be paid in order to acquire crossveinless-ness (cve and the associated phenotypes).