scholarly journals Biophysics and population size constrains speciation in an evolutionary model of developmental system drift

2019 ◽  
Vol 15 (7) ◽  
pp. e1007177 ◽  
Author(s):  
Bhavin S. Khatri ◽  
Richard A. Goldstein
Keyword(s):  
Population Size ◽  
Evolutionary Model ◽  
Developmental System ◽  
Developmental System Drift

scholarly journals Biophysics and population size constrains speciation in an evolutionary model of developmental system drift

2017 ◽  
Author(s):  
Bhavin S. Khatri ◽  
Richard A. Goldstein
Keyword(s):  
Population Size ◽  
Large Population ◽  
Evolutionary Model ◽  
Closely Related Species ◽  
Developmental System ◽  
Diffusive Growth ◽  
Developmental System Drift ◽  
Population Sizes ◽  
Mechanistic Basis ◽  
Molecular Phenotypes

Developmental system drift is a likely mechanism for the origin of hybrid incompatibilities between closely related species. We examine here the detailed mechanistic basis of hybrid incompatibilities for a genotype-phenotype map for developmental system drift under stabilising selection, where the organismal phenotype is conserved, but the underlying molecular phenotypes and genotype can drift. This leads to number of emergent phenomenon not obtainable by modelling genotype or phenotype alone. Our results show that: 1) speciation is more rapid at smaller population sizes with a characteristic, Orr-like, power law, but at large population sizes slow, characterised by a sub-diffusive growth law; 2) the molecular phenotypes under weakest selection contribute to the earliest incompatibilities; and 3) pairwise incompatibilities dominate over higher order, contrary to previous predictions that the latter should dominate. Our results indicate that biophysics and population size provide a much stronger constraint to speciation than suggested by previous models.

scholarly journals Polygenic local adaptation in metapopulations: a stochastic eco-evolutionary model

2020 ◽  
Author(s):  
Enikő Szép ◽  
Himani Sachdeva ◽  
Nick Barton
Keyword(s):  
Population Size ◽  
Local Adaptation ◽  
Genetic Drift ◽  
Diffusion Approximation ◽  
Joint Distribution ◽  
Evolutionary Model ◽  
Ecological Niches ◽  
Demographic Stochasticity ◽  
Linkage Disequilibria ◽  
Population Sizes

AbstractThis paper analyses the conditions for local adaptation in a metapopulation with infinitely many islands under a model of hard selection, where population size depends on local fitness. Each island belongs to one of two distinct ecological niches or habitats. Fitness is influenced by an additive trait which is under habitat-dependent directional selection. Our analysis is based on the diffusion approximation and accounts for both genetic drift and demographic stochasticity. By neglecting linkage disequilibria, it yields the joint distribution of allele frequencies and population size on each island. We find that under hard selection, the conditions for local adaptation in a rare habitat are more restrictive for more polygenic traits: even moderate migration load per locus at very many loci is sufficient for population sizes to decline. This further reduces the efficacy of selection at individual loci due to increased drift and because smaller populations are more prone to swamping due to migration, causing a positive feedback between increasing maladaptation and declining population sizes. Our analysis also highlights the importance of demographic stochasticity, which exacerbates the decline in numbers of maladapted populations, leading to population collapse in the rare habitat at significantly lower migration than predicted by deterministic arguments.

AN EVOLUTIONARY MODEL BASED ON BIT-STRING WITH INTELLIGENCE

2005 ◽  
Vol 16 (08) ◽  
pp. 1303-1309 ◽  
Author(s):  
MINGFENG HE ◽  
QIUHUI PAN ◽  
BINGLIN YU
Keyword(s):  
Population Size ◽  
Evolutionary Model ◽  
Model Based ◽  
Penna Model ◽  
Effect Of Food ◽  
Set Up

An evolutionary model based on bit-strings with intelligence is set up in this paper. In this model, gene is divided into two parts which relative to health and intelligence. The accumulated intelligence influences the survival process by the effect of food and space restrictions. We modify the Verhulst factor to study this effect. Both asexual and sexual model are discussed in this paper. The results show that after many time steps, stability is reached and the population self-organizes, just like the standard Penna model. The intelligence made the equilibrium to be reached larger both in asexual model and sexual model. Compared with asexual model the population size fluctuates more strongly in the sexual model.

Developmental variations among Panagrolaimid nematodes indicate developmental system drift within a small taxonomic unit

2014 ◽  
Vol 224 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Philipp H. Schiffer ◽  
Ndifon A. Nsah ◽  
Henny Grotehusmann ◽  
Michael Kroiher ◽  
Curtis Loer ◽  
...  
Keyword(s):  
Developmental System ◽  
Developmental System Drift ◽  
Developmental Variations

scholarly journals Patterns of putative gene loss suggest rampant developmental system drift in nematodes

2019 ◽  
Author(s):  
Gavin C. Woodruff
Keyword(s):  
Gene Loss ◽  
Developmental Stages ◽  
Genetic Research ◽  
Cell Lineage ◽  
Model Systems ◽  
Comparative Approach ◽  
Putative Gene ◽  
Developmental System ◽  
C Elegans ◽  
Developmental System Drift

AbstractGene loss often contributes to the evolution of adaptive traits. Conversely, null mutations frequently reveal no obvious phenotypic consequences. How pervasive is gene loss, what kinds of genes are dispensable, and what are the consequences of gene loss? The nematode Caenorhabditis elegans has long been at the forefront of genetic research, yet only recently have genomic resources become available to situate this species in its comparative phylogenetic and evolutionary context. Here, patterns of gene loss within Caenorhabditis are evaluated using 28 nematode genomes (most of them sequenced only in the past few years). Orthologous genes detected in every species except one were defined as being lost within that species. Putative functional roles of lost genes were determined using phenotypic information from C. elegans WormBase ontology terms as well as using existing C. elegans transcriptomic datasets. All species have lost multiple genes in a species-specific manner, with a genus-wide average of several dozen genes per species. Counterintuitively, nearly all species have lost genes that perform essential functions in C. elegans (an average of one third of the genes lost within a species). Retained genes reveal no differences from lost genes in C. elegans transcriptional abundance across all developmental stages when considering all 28 Caenorhabitis genomes. However, when considering only genomes in the subgeneric Elegans group, lost genes tend to have lower expression than retained genes. Taken together, these results suggest that the genetics of developmental processes are evolving rapidly despite a highly conserved adult morphology and cell lineage in this group, a phenomenon known as developmental system drift. These patterns highlight the importance of the comparative approach in interpreting findings in model systems genetics.

scholarly journals Comparative RNAi Screens in C. elegans and C. briggsae Reveal the Impact of Developmental System Drift on Gene Function

PLoS Genetics ◽  
2014 ◽  
Vol 10 (2) ◽  
pp. e1004077 ◽  
Author(s):  
Adrian J. Verster ◽  
Arun K. Ramani ◽  
Sheldon J. McKay ◽  
Andrew G. Fraser
Keyword(s):  
Gene Function ◽  
Developmental System ◽  
C Elegans ◽  
Developmental System Drift ◽  
The Impact
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