scholarly journals Evolution in eggs and phases: experimental evolution of fecundity and reproductive timing in Caenorhabditis elegans

2016 ◽  
Vol 3 (11) ◽  
pp. 160496 ◽  
Author(s):  
Bradly Alicea
Keyword(s):  
Natural Selection ◽  
Caenorhabditis Elegans ◽  
Experimental Evolution ◽  
Specific Gene ◽  
Reproductive Timing ◽  
Genetic Strains ◽  
Selection For ◽  
Carry Over ◽  
Strain Dependent

To examine the role of natural selection in fecundity in a variety of Caenorhabditis elegans genetic backgrounds, we used an experimental evolution protocol to evolve 14 distinct genetic strains over 15–20 generations. We were able to generate 790 distinct genealogies, which provided information on both the effects of natural selection and the evolvability of each strain. Among these genotypes are a wild-type (N2) and a collection of mutants with targeted mutations in the daf-c, daf-d and AMPK pathways. Differences are observed in reproductive fitness along with related changes in reproductive timing. The majority of selective effects on fecundity occur during the first few generations of evolution, while the negative selection for reproductive timing occurs on longer time scales. In addition, positive selection on fecundity results in positive and negative strain-dependent selection on reproductive timing. A derivative of population size per generation called reproductive carry-over (RCO) may be informative in terms of developmental selection. While these findings transcend mutations in a specific gene, changes in the RCO measure may nevertheless be products of selection. In conclusion, the broader implications of these findings are discussed, particularly in the context of genotype-fitness maps and the role of uncharacterized mutations in individual variation and evolvability.

scholarly journals Evolution in Eggs and Phases: experimental evolution of fecundity and reproductive timing in Caenorhabditis elegans

2016 ◽  
Author(s):  
Bradly Alicea
Keyword(s):  
Natural Selection ◽  
Caenorhabditis Elegans ◽  
Experimental Evolution ◽  
Negative Selection ◽  
Specific Gene ◽  
Reproductive Timing ◽  
Genetic Strains ◽  
Carry Over ◽  
Strain Dependent

ABSTRACTTo examine the role of natural selection on fecundity in a variety of Caenorhabditis elegans genetic backgrounds, we used an experimental evolution protocol to evolve 14 distinct genetic strains over 15-20 generations. Beginning with three founder worms for each strain, we were able to generate 790 distinct genealogies, which provided information on both the effects of natural selection and the evolvability of each strain. Among these genotypes are a wildtype (N2) and a collection of mutants with targeted mutations in the daf-c, daf-d, and AMPK pathways. The overarching goal of our analysis is two-fold: to observe differences in reproductive fitness and observe related changes in reproductive timing. This yields two outcomes. The first is that the majority of selective effects on fecundity occur during the first few generations of evolution, while the negative selection for reproductive timing occurs on longer timescales. The second finding reveals that positive selection on fecundity results in positive and negative selection on reproductive timing, both of which are strain-dependent. Using a derivative of population size per generation called the reproductive carry-over (RCO) measure, it is found that the fluctuation and shape of the probability distribution may be informative in terms of developmental selection. While these consist of general patterns that transcend mutations in a specific gene, changes in the RCO measure may nevertheless be products of selection. In conclusion, we discuss the broader implications of these findings, particularly in the context of genotype-fitness maps and the role of uncharacterized mutations in individual variation and evolvability.

scholarly journals Natural Selection at an Exceptionally Long GGC Repeat in the Human RASGEF1C and Divergent Genotypes in Late-onset Neurocognitive Disorder

2021 ◽  
Author(s):  
Z Jafarian ◽  
S Khamse ◽  
H Afshar ◽  
Khorram Khorshid HR ◽  
A Delbari ◽  
...  
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Late Onset ◽  
Core Promoter ◽  
Human Subjects ◽  
Specific Gene ◽  
Protein Coding ◽  
Repeat Allele ◽  
Complex Disorders ◽  
Selection For

Abstract Across the human protein-coding genes, the neuron-specific gene, RASGEF1C, contains the longest (GGC)-repeat, spanning its core promoter and 5′ untranslated region (RASGEF1C-201 ENST00000361132.9). RASGEF1C expression dysregulation occurs in late-onset neurocognitive disorders (NCDs), such as Alzheimer’s disease. Here we sequenced the GGC-repeat in a sample of human subjects (N = 269), consisting of late-onset NCDs (N = 115) and controls (N = 154). We also studied the status of this STR across vertebrates. The 6-repeat allele of this repeat was the predominant allele in the controls (frequency = 0.85) and NCD patients (frequency = 0.78). The NCD genotype compartment consisted of an excess of genotypes that lacked the 6-repeat (Mid-P exact = 0.004). We also detected divergent genotypes that were present in five NCD patients and not in the controls (Mid-P exact = 0.007). This STR expanded beyond 2-repeats specifically in primates, and was at maximum length in human. We conclude that there is natural selection for the 6-repeat allele of the RASGEF1C (GGC)-repeat in human, and significant divergence from that allele in late-onset NCDs. Indication of natural selection for predominantly abundant STR alleles and divergent genotypes enhance the perspective of evolutionary biology and disease pathogenesis in human complex disorders.

scholarly journals Experimental Evolution Reveals Antagonistic Pleiotropy in Reproductive Timing but Not Life Span in Caenorhabditis elegans

2011 ◽  
Vol 66A (12) ◽  
pp. 1300-1308 ◽  
Author(s):  
Jennifer L. Anderson ◽  
Rose M. Reynolds ◽  
Levi T. Morran ◽  
Julie Tolman-Thompson ◽  
Patrick C. Phillips
Keyword(s):  
Caenorhabditis Elegans ◽  
Life Span ◽  
Experimental Evolution ◽  
Antagonistic Pleiotropy ◽  
Reproductive Timing

scholarly journals Reply to Grossman: The role of natural selection for the increase of Caesarean section rates

2017 ◽  
Vol 114 (8) ◽  
pp. E1305-E1305 ◽  
Author(s):  
Philipp Mitteroecker ◽  
Simon M. Huttegger ◽  
Barbara Fischer ◽  
Mihaela Pavlicev
Keyword(s):  
Natural Selection ◽  
Caesarean Section ◽  
Selection For

The Role of Translocation and Selection in the Emergence of Genetic Clusters and Modules

2007 ◽  
Vol 13 (3) ◽  
pp. 249-258 ◽  
Author(s):  
David Newth ◽  
David G. Green
Keyword(s):  
Natural Selection ◽  
Essential Genes ◽  
Simulation Experiments ◽  
Junk Dna ◽  
Functional Cluster ◽  
Genetic Translocation ◽  
Genetic Clusters ◽  
Selection For

Biomolecular studies point increasingly to the importance of modularity in the organization of the genome. Processes such as the maintenance of metabolism are controlled by suites of genes that act as distinct, self-contained units, or modules. One effect is to promote stability of inherited characters. Despite the obvious importance of genetic modules, the mechanisms by which they form and persist are not understood. One clue is that functionally related genes tend to cluster together. Here we show that genetic translocation, recombination, and natural selection play a central role in this process. We distill the question of emerging genetic modularity into three simulation experiments that show: (1) a tendency, under natural selection, for essential genes to co-locate on the same chromosome and to settle in fixed loci; (2) that genes associated with a particular function tend to form functional clusters; and (3) that genes within a functional cluster tend to become arranged in transcription order. The results also imply that high proportions of junk DNA are essential to the process.

scholarly journals Hemoglobin E, malaria and natural selection

2019 ◽  
Vol 2019 (1) ◽  
pp. 232-241
Author(s):  
Jiwoo Ha ◽  
Ryan Martinson ◽  
Sage K Iwamoto ◽  
Akihiro Nishi
Keyword(s):  
Natural Selection ◽  
Malaria Infection ◽  
Meta Analysis ◽  
Evolutionary Genetics ◽  
Protective Role ◽  
Epidemiologic Studies ◽  
Hemoglobin E ◽  
Selection For

Abstract It is known that there has been positive natural selection for hemoglobin S and C in humans despite negative health effects, due to its role in malaria resistance. However, it is not well understood, if there has been natural selection for hemoglobin E (HbE), which is a common variant in Southeast Asia. Therefore, we reviewed previous studies and discussed the potential role of natural selection in the prevalence of HbE. Our review shows that in vitro studies, evolutionary genetics studies and epidemiologic studies largely support an involvement of natural selection in the evolution of HbE and a protective role of HbE against malaria infection. However, the evidence is inconsistent, provided from different regions, and insufficient to perform an aggregated analysis such as a meta-analysis. In addition, few candidate gene, genome-wide association or epistasis studies, which have been made possible with the use of big data in the post-genomic era, have investigated HbE. The biological pathways linking HbE and malaria infection have not yet been fully elucidated. Therefore, further research is necessary before it can be concluded that there was positive natural selection for HbE due to protection against malaria. Lay summary: Our review shows that evidence largely supports an involvement of natural selection in the evolution of HbE and a protective role of HbE against malaria. However, the evidence is not consistent. Further research is necessary before it is concluded.

Darwin’s politics of selection

2019 ◽  
Vol 38 (1) ◽  
pp. 72-102
Author(s):  
Luis Manuel Sanchez
Keyword(s):  
Natural Selection ◽  
Artificial Selection ◽  
Social Evolution ◽  
Human Consciousness ◽  
Natural Evolution ◽  
Conventional Model ◽  
Selection For ◽  
Survival Of The Fittest ◽  
Descent Of Man

The uses of natural selection argument in politics have been constant since Charles Darwin’s times. They have also been varied. The readings of Darwin’s theory range from the most radically individualist views, as in orthodox socio-Darwinism, to the most communitarian, as in Peter Kropotkin’s and other socialist perspectives. This essay argues that such diverse, contradictory, and sometimes even outrageous political derivations from Darwin’s theory may be partially explained by some incompleteness and ambivalences underlying Darwin’s concepts. “Natural selection,” “struggle for existence,” and “survival of the fittest” are open concepts and may suggest some hierarchical and segregationist interpretations. Circumstantially, Darwin accepted social “checks,” such as discouraging marriage of “lower” individuals to prevent them from reproducing, in a vein of Malthusian politics. This makes Darwin’s theory of selection by struggle collide with his theory of social instincts, by which he explains the origins of morality. It also favors reading Darwin’sOn the Origin of SpeciesorThe Descent of Manfrom opposite, mostly ideological perspectives. Darwin’s position is ambivalent, although hardly unreasonable. The recognition he makes of social instincts, as well as the use of the concept of artificial selection, entails accepting the role of human consciousness, by which social evolution cannot be reduced to natural evolution, as socio-Darwinians did next and as some neo-Darwinists seem to repeat. On these grounds, this essay argues the inadequacy of the conventional model of natural selection for understanding politics. If we want to describe politics in Darwin’s language,artificialrather thannatural selectionwould be the concept that performs better for explaining the courses of politics in real society.

scholarly journals The role of hermaphrodites in the experimental evolution of increased outcrossing rates in Caenorhabditis elegans

2014 ◽  
Vol 14 (1) ◽  
pp. 116 ◽  
Author(s):  
Sara Carvalho ◽  
Ivo M Chelo ◽  
Christine Goy ◽  
Henrique Teotónio
Keyword(s):  
Caenorhabditis Elegans ◽  
Experimental Evolution ◽  
Outcrossing Rates
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