Effects of artificial stabilizing selection on Drosophila populations subjected to directional selection for another trait

Genetica ◽  
1991 ◽  
Vol 83 (3) ◽  
pp. 247-256
Author(s):  
A. G. Imasheva ◽  
L. A. Zhivotovsky ◽  
O. E. Lazebny
Keyword(s):  
Directional Selection ◽  
Stabilizing Selection ◽  
Selection For

scholarly journals Does Long-Term Selection for Development Time Result in Canalization: A Test UsingDrosophila melanogaster

2019 ◽  
Author(s):  
Shampa M. Ghosh ◽  
K. M. Satish ◽  
J. Mohan ◽  
Amitabh Joshi
Keyword(s):  
Adult Development ◽  
Development Time ◽  
Larval Density ◽  
Directional Selection ◽  
Stabilizing Selection ◽  
Clear Trend ◽  
Population Means ◽  
Evolutionary Changes ◽  
Selection For

AbstractCanalization denotes the robustness of a trait against genetic or environmental perturbation. Plasticity, in contrast indicates the environmental sensitivity of a trait. Stabilizing selection is thought to increase canalization of a trait, whereas directional selection is often thought to lead to decanalization. However, the relationship between selection, canalization and plasticity remains largely unclear. Experimental evolution is a powerful approach for addressing fundamental questions in evolution. Here, we ask whether long-term directional selection for reduced pre-adult development time inDrosophila melanogasterresults in the evolution of increased canalization for development time, the trait under primary selection. We additionally investigate whether pre-adult survivorship, a trait only secondarily under selection in this experimental regime, also evolves to become canalized. We examine canalization both in terms of stability of population means and of within population variability across two environmental axes. We used four large outbred populations ofD. melanogasterselected for rapid pre-adult development and early reproduction for 295 generations, and four corresponding ancestral control populations that were not under conscious selection for development time or early reproduction. The selected populations had evolved 25% reduction in both development time and pre-adult survivorship at the time of this study. We studied development time and pre-adult survivorship of the selected populations and controls across various combinations ofrearing temperature and larval density. Development time in the selected populations had become more canalized than controls with regard to density, but not temperature. Canalization of development time across density appears to have evolved due to evolutionary changes in the lifehistory and physiology of the selected populations. Pre-adult survivorship, only a secondary correlate of fitness in the selected populations, did not show any clear trend in terms of canalization with regard to either density or temperature, and, overall variation in the trait was greater compared to development time within and across environments. Whether long-term directional selection canalizes or not, therefore, appears to be dependent in a complex way on specific interactions of trait, selection regime and environmental factor in the context of the ecology and physiology of the popualtions under study.

Anthropometric measurements and Darwinian fitness

1981 ◽  
Vol 13 (3) ◽  
pp. 309-316 ◽  
Author(s):  
William H. Mueller ◽  
Gabriel W. Lasker ◽  
F. Gaynor Evans
Keyword(s):  
Marital Status ◽  
Physical Characteristics ◽  
Directional Selection ◽  
Anthropometric Measurements ◽  
One Dimension ◽  
Stabilizing Selection ◽  
Darwinian Fitness ◽  
Selection For ◽  
The Relationship ◽  
Destabilizing Selection

SummaryThe relationship between anthropometrics and three measures of Darwinian fitness—number of surviving children, number of living siblings and marital status—was sought in a population practising no contraception. The pattern suggestive of stabilizing selection was evident for one dimension, destabilizing selection for another dimension, and directional selection for yet another. The dimensions studied were those least intercorrelated one with another. Stabilizing selection for human physical characteristics may not be a universal phenomenon.

scholarly journals Stabilizing selection on individual pattern elements of aposematic signals

2017 ◽  
Vol 284 (1861) ◽  
pp. 20170926 ◽  
Author(s):  
Anne E. Winters ◽  
Naomi F. Green ◽  
Nerida G. Wilson ◽  
Martin J. How ◽  
Mary J. Garson ◽  
...  
Keyword(s):  
Pattern Analysis ◽  
Marine Organism ◽  
Warning Signal ◽  
Colour Pattern ◽  
Stabilizing Selection ◽  
Warning Signals ◽  
Fish Predator ◽  
Selection For ◽  
Aposematic Signals ◽  
Behavioural Experiments

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus , which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus , used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.

scholarly journals Substitution Rates Under Stabilizing Selection

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 479-486
Author(s):  
Alan Hastings
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Quantitative Traits ◽  
Strong Dependence ◽  
Phenotypic Selection ◽  
Analytical Models ◽  
Stabilizing Selection ◽  
Substitution Rates ◽  
Quantitative Characters ◽  
Selection For

ABSTRACT Allelic substitutions under stabilizing phenotypic selection on quantitative traits are studied in Monte Carlo simulations of 8 and 16 loci. The results are compared and contrasted to analytical models based on work of M. Kimura for two and "infinite" loci. Selection strengths of S = 4Nes approximately four (which correspond to reasonable strengths of selection for quantitative characters) can retard substitution rates tenfold relative to rates under neutrality. An important finding is a strong dependence of per locus substitution rates on the number of loci.

scholarly journals Selection for recombination in a polygenic model – the mechanism

1988 ◽  
Vol 51 (1) ◽  
pp. 59-63 ◽  
Author(s):  
J. Maynard Smith
Keyword(s):  
Linkage Disequilibrium ◽  
Recombination Rate ◽  
Phenotypic Variability ◽  
Directional Selection ◽  
Polygenic Model ◽  
Infinite Population ◽  
Selection For ◽  
Repulsion Linkage

SummaryA polygenic model has been simulated in order to reveal the process whereby selection in an infinite population can lead to an increase in the frequency of alleles causing higher rates of recombination (CH alleles). Directional selection generates repulsion linkage disequilibrium (+ − + −), which is less strong in CH gametes (gametes carrying CH alleles). In consequence, CH gametes contribute greater phenotypic variability, and therefore respond more to directional selection: that is, they accumulate more selectively favoured alleles. CH alleles then increase in frequency by hitch-hiking. In contrast, normalizing selection, or frequent changes in the direction of selection, favour alleles for a low recombination rate.

scholarly journals Quantitative genetic variability maintained by mutation-stabilizing selection balance: sampling variation and response to subsequent directional selection

1989 ◽  
Vol 54 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Peter D. Keightley ◽  
William G. Hill
Keyword(s):  
Genetic Variance ◽  
Directional Selection ◽  
Quantitative Character ◽  
Stabilizing Selection ◽  
Effective Population ◽  
Selection Responses ◽  
Quantitative Genetic ◽  
Before And After ◽  
Cage Population ◽  
Selection Of

SummaryA model of genetic variation of a quantitative character subject to the simultaneous effects of mutation, selection and drift is investigated. Predictions are obtained for the variance of the genetic variance among independent lines at equilibrium with stabilizing selection. These indicate that the coefficient of variation of the genetic variance among lines is relatively insensitive to the strength of stabilizing selection on the character. The effects on the genetic variance of a change of mode of selection from stabilizing to directional selection are investigated. This is intended to model directional selection of a character in a sample of individuals from a natural or long-established cage population. The pattern of change of variance from directional selection is strongly influenced by the strengths of selection at individual loci in relation to effective population size before and after the change of regime. Patterns of change of variance and selection responses from Monte Carlo simulation are compared to selection responses observed in experiments. These indicate that changes in variance with directional selection are not very different from those due to drift alone in the experiments, and do not necessarily give information on the presence of stabilizing selection or its strength.

ESTIMATION OF GENERAL AND SPECIFIC COMBINING ABILITIES IN POTATO

1976 ◽  
Vol 18 (3) ◽  
pp. 463-470 ◽  
Author(s):  
G.C.C. Tai
Keyword(s):  
Solanum Tuberosum ◽  
Specific Gravity ◽  
Combining Ability ◽  
Solanum Tuberosum L ◽  
High Yield ◽  
Average Weight ◽  
Stabilizing Selection ◽  
Low Frequencies ◽  
Significant Difference ◽  
Selection For

Seven quantitative traits of the cultivated potato (Solanum tuberosum L.) were studied in a partial diallel cross experiment. Large specific combining ability effects were observed for total and marketable yields, total number of tubers, and number of marketable tubers. Large general combining ability effects were obtained for average weight per tuber, average weight per marketable tuber, and specific gravity. The SCA effect for specific gravity was also significant. It is suggested that the difference of combining ability performance noted above for the two yield components was due to a long history of directional selection for high yield and stabilizing selection for tubers within the marketable size range. There were low frequencies of both GCA and SCA effects showing significant difference from the population mean. This is interpreted as an affirmation of the narrow genetic base which exists in the present gene pool in Solanum tuberosum. Heritability estimates based on GCA effects indicated that parents can be efficiently selected for average tuber weight and specific gravity.

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