EVOLUTION OF ADDITIVE AND NONADDITIVE GENETIC VARIANCE IN DEVELOPMENT TIME ALONG A CLINE IN DROSOPHILA SERRATA

Evolution ◽  
2003 ◽  
Vol 57 (8) ◽  
pp. 1846 ◽  
Author(s):  
Carla M. Sgrò ◽  
Mark W. Blows
Keyword(s):  
Development Time ◽  
Genetic Variance ◽  
Drosophila Serrata

scholarly journals Artificial selection on male size depletes genetic variance but not covariance of life history traits in the yellow dung fly

2019 ◽  
Author(s):  
WU Blanckenhorn ◽  
V Llaurens ◽  
C Reim ◽  
Y Teuschl ◽  
E Postma
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Body Size ◽  
Artificial Selection ◽  
Development Time ◽  
Life History Traits ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Male Size ◽  
First Clutch

SUMMARYThe evolutionary potential of organisms depends on the presence of sufficient genetic variation for traits subject to selection, as well as on the genetic covariances among them. While genetic variation ultimately derives from mutation, theory predicts the depletion of genetic (co)variation under consistent directional or stabilizing selection in natural populations. We estimated and compared additive genetic (co)variances for several standard life history traits, including some for which this has never been assessed, before and after 24 generations of artificial selection on male size in the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) using a series of standard half-sib breeding experiments. As predicted, genetic variances (VA), heritabilities (h2) and evolvabilities (IA) of body size, development time, first clutch size, and female age at first clutch were lower after selection. As independent selection lines were crossed prior to testing, we can rule out that this reduction is due to genetic drift. In contrast to the variances, and against expectation, the additive genetic correlations between the sexes for development time and body size remained strong and positive (rA = 0.8–0.9), while the genetic correlation between these traits within the sexes tended to strengthen (but not significantly so). Our study documents that the effect of selection on genetic variance is predictable, whereas that on genetic correlations is not.

scholarly journals No support for intra-nor inter-locus sexual conflict over mating latency and copulation duration in a polyandrous fruit fly

2020 ◽  
Author(s):  
Julie M. Collet ◽  
Jacqueline L Sztepanacz
Keyword(s):  
Sexual Conflict ◽  
Genetic Variance ◽  
Fruit Fly ◽  
The Other ◽  
Copulation Duration ◽  
Total Strength ◽  
Male And Female ◽  
Male Attractiveness ◽  
Mating Latency ◽  
Drosophila Serrata

AbstractThe total strength of sexual selection on males depends on the relationship between various components of pre- and post-copulatory fitness. Misalignment between male and female interests creates inter-locus sexual conflict, where the fitness of one sex is increased at the expense of the other. Although rarely considered, mating behaviours can also be genetically correlated between males and females, creating intra-locus sexual conflict, where beneficial alleles in one sex are costly when expressed in the other sex. How inter- and intra-locus sexual conflicts operate on the expression of mating behaviours remains little understood. Here, we study male attractiveness, mating latency and copulation duration in two populations of the polyandrous Drosophila serrata. Univariate analyses show little genetic variance in mating latency, and that males, but not females, contribute to copulation duration genetic variance. Further, multivariate analyses revealed little covariance between the studied traits. However, analyses considering male and female contribution in a single framework supported genetic contributions from both sexes for mating behaviours and complex patterns of between sexes correlations. Finally, our study did not find any association between those mating behaviours and fitness component, specifically (i) no phenotypic covariance between male attractiveness and mating latency and, (ii) longer copulations did not result in the production of more offspring. With no detectable fitness benefits in any sexes for shorter mating latency or longer copulation duration, our results do not support the presence of inter-nor intra-locus sexual conflict for these mating traits.

scholarly journals The effects of stabilizing selection on the time of development in Drosophila melanogaster

1962 ◽  
Vol 3 (3) ◽  
pp. 364-382 ◽  
Author(s):  
Timothy Prout
Keyword(s):  
Drosophila Melanogaster ◽  
Development Time ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Parallel Line ◽  
Total Variance ◽  
Disruptive Selection ◽  
Stabilizing Selection ◽  
Environmental Component ◽  
The Mean

The length of time of development, from oviposition to emergence in Drosophila melanogaster was subjected to stabilizing selection. In each generation only the individuals emerging close to the mean development time were used as parents of the next generation. This line was designated the ‘S’ line. In a parallel line disruptive selection was practised; where in each generation the earliest flies to emerge were mated to the flies last to emerge; those emerging at intermediate times were discarded. This line was designated the ‘D’ line. Two control lines were also carried, where the flies were mated at random with respect to time of emergence. The experiment extended for 40 generations and produced the following results:(1) The variance of development time decreased in the S line and increased in the D line, relative to the control lines.(2) The mean development time decreased in the S line and increased in the D line.(3) The coefficients of variation decreased in the S line and increased in the D line.(4) The viability, measured as per cent flies emerging, decreased in the D line.Toward the end of the experiment the amount of additive genetic variance in the selected lines and in the control lines was estimated from the response to directional selection. The estimates showed that (i) the loss of total variance in the S line can be accounted for completely by a loss in additive genetic variance, and (ii) the increase in the total variance of the D line cannot be ascribed to an increase in the additive genetic variance. It was probably due to an increase in the environmental component of variance, i.e. to a loss of ‘buffering capacity’.

scholarly journals The contribution of mutation and selection to multivariate quantitative genetic variance in an outbred population of Drosophila serrata

2021 ◽  
Vol 118 (31) ◽  
pp. e2026217118
Author(s):  
Robert J. Dugand ◽  
J. David Aguirre ◽  
Emma Hine ◽  
Mark W. Blows ◽  
Katrina McGuigan
Keyword(s):  
Genetic Variance ◽  
Genetic Correlations ◽  
Stabilizing Selection ◽  
Outbred Population ◽  
Drosophila Serrata ◽  
Slow Evolution ◽  
Multivariate Traits ◽  
Mutational Variance ◽  
Mutation And Selection ◽  
Multivariate Phenotypes

Genetic variance is not equal for all multivariate combinations of traits. This inequality, in which some combinations of traits have abundant genetic variation while others have very little, biases the rate and direction of multivariate phenotypic evolution. However, we still understand little about what causes genetic variance to differ among trait combinations. Here, we investigate the relative roles of mutation and selection in determining the genetic variance of multivariate phenotypes. We accumulated mutations in an outbred population of Drosophila serrata and analyzed wing shape and size traits for over 35,000 flies to simultaneously estimate the additive genetic and additive mutational (co)variances. This experimental design allowed us to gain insight into the phenotypic effects of mutation as they arise and come under selection in naturally outbred populations. Multivariate phenotypes associated with more (less) genetic variance were also associated with more (less) mutational variance, suggesting that differences in mutational input contribute to differences in genetic variance. However, mutational correlations between traits were stronger than genetic correlations, and most mutational variance was associated with only one multivariate trait combination, while genetic variance was relatively more equal across multivariate traits. Therefore, selection is implicated in breaking down trait covariance and resulting in a different pattern of genetic variance among multivariate combinations of traits than that predicted by mutation and drift. Overall, while low mutational input might slow evolution of some multivariate phenotypes, stabilizing selection appears to reduce the strength of evolutionary bias introduced by pleiotropic mutation.

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