scholarly journals Recombination in a natural population of the bdelloid rotifer Adineta vaga

2018 ◽  
Author(s):  
Olga A. Vakhrusheva ◽  
Elena A. Mnatsakanova ◽  
Yan R. Galimov ◽  
Tatiana V. Neretina ◽  
Evgeny S. Gerasimov ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Adaptive Radiation ◽  
Wild Population ◽  
Bdelloid Rotifer ◽  
Bdelloid Rotifers ◽  
Stick Insects ◽  
Complete Genomes ◽  
Long Term Consequences ◽  
Rule Out

Sexual reproduction which involves alternation of meiosis and syngamy is the ancestral condition of extant eukaryotes. Transitions to asexual reproduction were numerous, but most of the resulting eukaryotic lineages are rather short-lived. Still, there are several exceptions to this rule including darwinulid ostracods1,2 and timema stick insects3. The most striking of them is bdelloid rotifers4–6, microscopic freshwater invertebrates which underwent an extensive adaptive radiation after apparently losing meiosis over 10 Mya. Indeed, both the lack of males in numerous bdelloid species and the lack of proper homology between chromosomes6 rule out ordinary sex. However, this does not exclude the possibility of some other mode of interindividual genetic exchange and recombination in their populations7. Recent analyses based on a few loci suggested genetic exchanges in this group8,9, although this has been controversial10. Here, we compare complete genomes of 11 individuals from the wild population of the bdelloid rotifer Adineta vaga, and show that its genetic structure, which involves Hardy-Weinberg proportions of genotypes within loci and lack of linkage disequilibrium between distant loci, is incompatible with strictly clonal reproduction. Instead, it can emerge only under ongoing recombination between different individuals within this species, possibly through transformation. Such a genetic structure makes the population immune to negative long-term consequences of the loss of conventional meiosis11, although this does not necessarily imply that interindividual genetic exchanges in A. vaga are directly maintained by natural selection.

Justifying Too Much

2020 ◽  
pp. 419-434
Author(s):  
Bob Brecher
Keyword(s):  
Moral Theory ◽  
Long Term Consequences ◽  
Rule Out

In this chapter, I analyze the use and abuse of utilitarianism in the torture debate, arguing that the latter might turn out to be utilitarianism's nemesis. For what the debate lays bare is that, if we are to take utilitarianism seriously, then we must be prepared to torture the alleged terrorist's child, or indeed anyone at all, to prevent the so-called imminent catastrophe. Furthermore, if that conclusion is unpalatable on rule-utilitarian grounds—in terms of the institutional and long-term consequences of such a practice—then those same sorts of consideration rule out torturing the alleged terrorist themselves. That this is systematically obscured by those who would purport to justify interrogational torture by their being highly selective about the consequences they consider, and/or by arbitrarily “modifying” the scope of utilitarianism when it generates inconvenient conclusions, again suggests that utilitarianism may be fundamentally flawed; and that its use to defend interrogational torture shows this. The argument is in four sections: a refutation of the alleged necessity of interrogational torture in “ticking bomb” cases; an analysis of utilitarian proponents' of interrogational torture properly to understand that their utilitarianism cannot accommodate non-utilitarian limits when inconvenient; third, their failure to acknowledge the implications of that for the permissibility of torturing known innocents to force others to divulge information; and, fourth, how these considerations come together to suggest that utilitarianism might not be a moral theory at all.

Genomic Signature of Sexual Reproduction in the Bdelloid Rotifer Macrotrachella quadricornifera

Genetics ◽  
2021 ◽  
Author(s):  
Veronika N Laine ◽  
Timothy Sackton ◽  
Matthew Meselson
Keyword(s):  
Sexual Reproduction ◽  
Genomic Signature ◽  
Allele Sharing ◽  
Bdelloid Rotifer ◽  
Freshwater Invertebrates ◽  
Bdelloid Rotifers ◽  
Worldwide Distribution

Abstract Bdelloid rotifers, common freshwater invertebrates of ancient origin and worldwide distribution have long been thought to be entirely asexual, being the principal exception to the view that in eukaryotes the loss of sex leads to early extinction. That bdelloids are facultatively sexual is shown by a study of allele sharing within a group of closely related bdelloids of the species Macrotrachella quadricornifera, supporting the view that sexual reproduction is essential for long-term success in all eukaryotes.

Barriers to Physical Activity in Adolescents

2015 ◽  
Vol 23 (2) ◽  
pp. 47-59 ◽  
Author(s):  
Nadine Langguth ◽  
Tanja Könen ◽  
Simone Matulis ◽  
Regina Steil ◽  
Caterina Gawrilow ◽  
...  
Keyword(s):  
Physical Activity ◽  
Leisure Activities ◽  
Outcome Expectations ◽  
Multidimensional Approach ◽  
Factor Analyses ◽  
Physical And Mental Health ◽  
Tailored Interventions ◽  
Long Term Consequences ◽  
Age Range

During adolescence, physical activity (PA) decreases with potentially serious, long-term consequences for physical and mental health. Although barriers have been identified as an important PA correlate in adults, research on adolescents’ PA barriers is lacking. Thus reliable, valid scales to measure adolescents’ PA barriers are needed. We present two studies describing a broad range of PA barriers relevant to adolescents with a multidimensional approach. In Study 1, 124 adolescents (age range = 12 – 24 years) reported their most important PA barriers. Two independent coders categorized those barriers. The most frequent PA barriers were incorporated in a multidimensional questionnaire. In Study 2, 598 adolescents (age range = 13 – 21 years) completed this questionnaire and reported their current PA, intention, self-efficacy, and negative outcome expectations. Seven PA barrier dimensions (leisure activities, lack of motivation, screen-based sedentary behavior, depressed mood, physical health, school workload, and preconditions) were confirmed in factor analyses. A multidimensional approach to measuring PA barriers in adolescents is reliable and valid. The current studies provide the basis for developing individually tailored interventions to increase PA in adolescents.

Responding to Immediate and Long-Term Consequences of Terror

2008 ◽  
Author(s):  
Mary Fabri ◽  
Amber Gray ◽  
Jeannette Uwineza
Keyword(s):  
Long Term Consequences

Themes, Diction, and Prosodic Systems in Yoruba Lullabies

2019 ◽  
Vol 12 (1) ◽  
pp. 18-33 ◽  
Author(s):  
Olusanmi Babarinde ◽  
Elizabeth Babarinde
Keyword(s):  
Participant Observation ◽  
Cultural Beliefs ◽  
Survey Method ◽  
World Views ◽  
Scholarly Research ◽  
Long Term Consequences ◽  
Analyse Data ◽  
Descriptive Survey ◽  
Future Learning

Lullabies are essentially sung for their soothing nature but, as this article shows, they have other important functions. One of the most important of these is that lullabies may provide much-needed language stimulation with important long-term consequences for future learning. This paper begins the work of addressing the dearth of scholarly research on lullabies, especially in the Yoruba (Nigeria: Niger-Congo) culture. It looks at the range of themes, dictions, and prosody that are intertwined to reveal Yoruba beliefs and world-views about children, starting with their time in the womb. The study uses a descriptive survey method to analyse data collected through participant observation. It shows that Yoruba lullabies not only offer insights into Yoruba cultural beliefs but also depend greatly on figurative expression and prosodic systems. These rich literary qualities identify lullabies as the earliest sub-genre of children's poetry.

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