scholarly journals Heritability of Directional Asymmetry in Drosophila melanogaster

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Ashley J. R. Carter ◽  
Elizabeth Osborne ◽  
David Houle
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Artificial Selection ◽  
Natural Variation ◽  
The Other ◽  
Directional Asymmetry ◽  
Consistent Difference ◽  
Selection Experiment ◽  
Response To Selection ◽  
Powerful Technique

Directional asymmetry (DA), the consistent difference between a pair of morphological structures in which the same side is always larger than the other, presents an evolutionary mystery. Although many paired traits show DA, genetic variation for DA has not been unambiguously demonstrated. Artificial selection is a powerful technique for uncovering selectable genetic variation; we review and critique the limited number of previous studies that have been performed to select on DA and present the results of a novel artificial selection experiment on the DA of posterior crossvein location in Drosophila wings. Fifteen generations of selection in two genetically distinct lines were performed and none of the lines showed a significant response to selection. Our results therefore support and reconfirm previous findings; despite apparent natural variation and evolution of DA in nature, DA remains a paradoxical trait that does not respond to artificial selection.

scholarly journals Genetic architecture of natural variation in visual senescence in Drosophila

2016 ◽  
Vol 113 (43) ◽  
pp. E6620-E6629 ◽  
Author(s):  
Mary Anna Carbone ◽  
Akihiko Yamamoto ◽  
Wen Huang ◽  
Rachel A. Lyman ◽  
Tess Brune Meadors ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Life Span ◽  
Candidate Genes ◽  
Natural Variation ◽  
Genetic Basis ◽  
Nervous System Development ◽  
Interindividual Variation ◽  
Human Populations ◽  
Age Dependent

Senescence, i.e., functional decline with age, is a major determinant of health span in a rapidly aging population, but the genetic basis of interindividual variation in senescence remains largely unknown. Visual decline and age-related eye disorders are common manifestations of senescence, but disentangling age-dependent visual decline in human populations is challenging due to inability to control genetic background and variation in histories of environmental exposures. We assessed the genetic basis of natural variation in visual senescence by measuring age-dependent decline in phototaxis using Drosophila melanogaster as a genetic model system. We quantified phototaxis at 1, 2, and 4 wk of age in the sequenced, inbred lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) and found an average decline in phototaxis with age. We observed significant genetic variation for phototaxis at each age and significant genetic variation in senescence of phototaxis that is only partly correlated with phototaxis. Genome-wide association analyses in the DGRP and a DGRP-derived outbred, advanced intercross population identified candidate genes and genetic networks associated with eye and nervous system development and function, including seven genes with human orthologs previously associated with eye diseases. Ninety percent of candidate genes were functionally validated with targeted RNAi-mediated suppression of gene expression. Absence of candidate genes previously implicated with longevity indicates physiological systems may undergo senescence independent of organismal life span. Furthermore, we show that genes that shape early developmental processes also contribute to senescence, demonstrating that senescence is part of a genetic continuum that acts throughout the life span.

scholarly journals The effect of suppressing crossing-over on the response to selection in Drosophila melanogaster

1970 ◽  
Vol 16 (1) ◽  
pp. 1-16 ◽  
Author(s):  
C. P. McPhee ◽  
Alan Robertson
Keyword(s):  
Drosophila Melanogaster ◽  
Dominant Gene ◽  
Crossing Over ◽  
Linkage Equilibrium ◽  
Selection Experiment ◽  
Base Population ◽  
Response To Selection ◽  
Wild Type ◽  
Segregation Ratios

SUMMARYA selection experiment for sternopleural bristles in Drosophila melanogaster was undertaken to measure the effect of suppressing crossing-over on chromosomes II and III using the inversions Curly and Moiré marked with a dominant gene, which severely reduce crossing-over. In one set of lines selected wild-type males were mated to selected females, heterozygous for Cy and Mé, and in a parallel set selected males carrying the inversions were mated to selected wild-type females. Because there is no crossing-over in the males in this species, crossing-over is much reduced in the first set and is at its usual level in the second. The effect of the selection was measured on flies which did not carry the inversions. The suppression of crossing-over reduced the advance at the limit by 28 ± 8% for selection upwards and by 22 ± 7% for selection downwards. The segregation ratios of the inversions were observed throughout the experiment. At the end, the proportion of wild-type flies emerging was not different in the two sets of lines. The results are consistent with an assumption of initial linkage equilibrium between loci affecting sternopleural bristles in the base population.

scholarly journals THE ORGANIZATION OF GENETIC VARIATION FOR RECOMBINATION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1986 ◽  
Vol 114 (2) ◽  
pp. 525-547
Author(s):  
Lisa D Brooks ◽  
R William Marks
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Population ◽  
Small Region ◽  
Crossing Over ◽  
Fine Scale ◽  
Response To Selection ◽  
Natural Genetic Variation ◽  
The Third ◽  
Scale Response

ABSTRACT The amount and form of natural genetic variation for recombination were studied in six lines for which second chromosomes were extracted from a natural population of Drosophila melanogaster. Multiply marked second, Χ and third chromosomes were used to score recombination. Recombination in the second chromosomes varied in both amount and distribution. These second chromosomes caused variation in the amount and distribution of crossing over in the Χ chromosome and also caused variation in the amount, but not the distribution, of crossing over in the third chromosome. The total amount of crossing over on a chromosome varied by 12-14%. One small region varied twofold; other regions varied by 16-38%. Lines with less crossing over on one chromosome generally had less crossing over on other chromosomes, the opposite of the standard interchromosomal effect. These results show that modifiers of recombination can affect more than one chromosome, and that the variation exists for fine-scale response to selection on recombination.

scholarly journals Polygenic mutation in Drosophila melanogaster: estimates from response to selection of inbred strains.

Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 937-951 ◽  
Author(s):  
T F Mackay ◽  
J D Fry ◽  
R F Lyman ◽  
S V Nuzhdin
Keyword(s):  
Drosophila Melanogaster ◽  
Artificial Selection ◽  
Inbred Strains ◽  
Response To Selection ◽  
Environmental Variance ◽  
Rapid Responses ◽  
Bristle Number ◽  
Mutational Variance ◽  
Selection Of ◽  
New Mutations

Abstract Replicated divergent artificial selection for abdominal and sternopleural bristle number from a highly inbred strain of Drosophila melanogaster resulted in an average divergence after 125 generations of selection of 12.0 abdominal and 8.2 sternopleural bristles from the accumulation of new mutations affecting bristle number. Responses to selection were highly asymmetrical, with greater responses for low abdominal and high sternopleural bristle numbers. Estimates of VM, the mutational variance arising per generation, based on the infinitesimal model and averaged over the responses to the first 25 generations of selection, were 4.32 x 10(-3) VE for abdominal bristle number and 3.66 x 10(-3) VE for sternopleural bristle number, where VE is the environmental variance. Based on 10 generations of divergent selection within lines from generation 93, VM for abdominal bristle number was 6.75 x 10(-3) VE and for sternopleural bristle number was 5.31 x 10(-3) VE. However, estimates of VM using the entire 125 generations of response to selection were lower and generally did not fit the infinitesimal model largely because the observed decelerating responses were not compatible with the predicted increasing genetic variance over time. These decelerating responses, periods of response in the opposite direction to artificial selection, and rapid responses to reverse selection all suggest new mutations affecting bristle number on average have deleterious effects on fitness. Commonly observed periods of accelerated responses followed by long periods of stasis suggest a leptokurtic distribution of mutational effects for bristles.

scholarly journals Recurrent evolution of cross-resistance in response to selection for improved post-infection survival in Drosophila melanogaster

2021 ◽  
Author(s):  
Aparajita Singh ◽  
Aabeer Basu ◽  
Biswajit Shit ◽  
Tejashwini Hegde ◽  
Nitin Bansal ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Bacterial Pathogen ◽  
Host Population ◽  
Host Susceptibility ◽  
Cross Resistance ◽  
Response To Selection ◽  
Host Sex ◽  
Determining Factors ◽  
Selection For

The host susceptibility to one pathogen can decrease, increase, or remain unaffected by virtue of the host evolving resistance towards a second pathogen. Negative correlations between a host susceptibility to different pathogens is an often-cited explanation for maintenance of genetic variation in immune function determining traits in a host population. In this study, we investigated the change in susceptibility of Drosophila melanogaster flies to various novel bacterial pathogens after being experimentally selected for increased resistance to one particular bacterial pathogen. We independently selected flies to become more resistant towards Enterococcus faecalis and Pseudomonas entomophila, and baring a few exceptions the evolved populations exhibited cross-resistance against the range of pathogens tested in the study. Neither the identity of the native pathogen nor the host sex was major determining factors in predicting the pattern of cross-resistance exhibited by the selected populations. We therefore report that a generalized cross-resistance to novel pathogens can repeatedly evolve in response to selection for resistance against a single pathogen.

scholarly journals TRANSPOSABLE ELEMENT-INDUCED RESPONSE TO ARTIFICIAL SELECTION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1985 ◽  
Vol 111 (2) ◽  
pp. 351-374
Author(s):  
Trudy F C Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Artificial Selection ◽  
Abdominal Tergite ◽  
P Element ◽  
Induced Response ◽  
Phenotypic Variance ◽  
P Elements ◽  
Insertion And Deletion ◽  
Multiple Copies

ABSTRACT The P family of transposable elements in Drosophila melanogaster transpose with exceptionally high frequency when males from P strains carrying multiple copies of these elements are crossed to females from M strains that lack P elements, but with substantially lower frequency in the reciprocal cross. Transposition is associated with enhanced mutation rates, caused by insertion and deletion of P elements, and chromosome rearrangements. If P element mutagenesis creates additional variation for quantitative traits, accelerated response to artificial selection of progeny of M♀♀ × P♂♂ strain crosses is expected, compared with that from progeny of P♀♀ × M♂♂ strain crosses.—Divergent artificial selection for number of bristles on the last abdominal tergite was carried out for 16 generations among the progeny of P–strain males (Harwich) and M–strain females (Canton-S) and also of M–strain males (Canton-S) and P-strain females (Harwich). Each cross was replicated four times. Average realized heritability of abdominal bristle score for the crosses in which P transposition was expected was 0.244 ± 0.017, 1.5 times greater than average heritability estimated from crosses in which transposition was expected to be rare (0.163 ± 0.010). Phenotypic variance of abdominal bristle score increased by a factor of four in lines selected from M♀♀ × P♂♂ crosses when compared with those selected from P♀♀ × M♂♂ hybrids. Not all quantitative genetic variation induced by P elements is additive. A substantial fraction of nonadditive genetic variation is implicated by chromosomal analysis, which demonstrates deleterious fitness effects of the mutations when homozygous.—Several putative "quantitative" mutations were identified from chromosomes extracted from the selected lines; these will form the basis for further investigation at the molecular level of the genes controlling quantitative inheritance.

scholarly journals Unusual genetic architecture of natural variation affecting drug resistance in Drosophila melanogaster

2002 ◽  
Vol 80 (3) ◽  
pp. 205-213 ◽  
Author(s):  
ROLAND CARRILLO ◽  
GREG GIBSON
Keyword(s):  
Drug Resistance ◽  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Genetic Architecture ◽  
Natural Variation ◽  
Starvation Resistance ◽  
Female Resistance ◽  
Caffeine Ingestion ◽  
Naturally Occurring ◽  
Chronic Ingestion

Naturally occurring genetic variation was quantified for survival time of adult Drosophila melanogaster exposed to chronic ingestion of the drugs nicotine, caffeine, dopamine, tyramine and octopamine. Responses to nicotine, tyramine and octopamine were genetically correlated in both sexes, whereas caffeine response correlated with starvation resistance. However, there is also genetic variation that is specific for each of the drugs. Females tended to be more resistant than males to nicotine and caffeine but sex-by-genotype interactions were also seen for these drugs and for the response to dopamine. An unusual and complex genetic architecture was observed in crosses between lines with different responses to caffeine ingestion. Additive and dominance components were clearly seen from the analysis of F1 individuals, but increased female resistance to caffeine in backcross generations and increased male sensitivity in F2 generations confused the interpretation of possible epistatic contributions.

scholarly journals Independent natural genetic variation of punishment- versus relief-memory

2016 ◽  
Vol 12 (12) ◽  
pp. 20160657 ◽  
Author(s):  
Mirjam Appel ◽  
Claus-Jürgen Scholz ◽  
Samet Kocabey ◽  
Sinead Savage ◽  
Christian König ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Variation ◽  
Fruit Fly ◽  
Inbred Strains ◽  
Adaptive Behaviour ◽  
Clinical Implications ◽  
Natural Genetic Variation ◽  
Study Case ◽  
Positive Valence

A painful event establishes two opponent memories: cues that are associated with pain onset are remembered negatively, whereas cues that coincide with the relief at pain offset acquire positive valence. Such punishment- versus relief-memories are conserved across species, including humans, and the balance between them is critical for adaptive behaviour with respect to pain and trauma. In the fruit fly, Drosophila melanogaster as a study case, we found that both punishment- and relief-memories display natural variation across wild-derived inbred strains, but they do not covary, suggesting a considerable level of dissociation in their genetic effectors. This provokes the question whether there may be heritable inter-individual differences in the balance between these opponent memories in man, with potential psycho-clinical implications.

scholarly journals GENETIC VARIATION FOR THE SEX RATIO IN NASONIA VITRIPENNIS

Genetics ◽  
1985 ◽  
Vol 110 (1) ◽  
pp. 93-105
Author(s):  
E Davis Parker ◽  
Steven Hecht Orzack
Keyword(s):  
Genetic Variation ◽  
Sex Ratio ◽  
Artificial Selection ◽  
Sex Ratios ◽  
Female Parent ◽  
Parasitoid Wasp ◽  
Selection Response ◽  
Inbred Lines ◽  
Selection Experiment ◽  
Nasonia Vitripennis

ABSTRACT We detected genetic variation for the sex ratio in the parasitoid wasp Nasonia vitripennis by analysis of inbred lines and with an artificial selection experiment. Sex ratios differed significantly among five independently isolated lines. Furthermore, sex ratio in broods produced by single females in single hosts shifted from 80-90% female to 50-55% female in 13 to 15 generations in each of two replicate selection lines. The final sex ratios of both selection lines were significantly lower than any of the inbred line sex ratios. Backcrosses revealed that the selection response was due to nuclear genes acting through the female parent. In light of known facultative sex ratio behavior and major genes affecting sex ratio in Nasonia, our results suggest that population and individual sex ratios in this species are molded by processes at both genetic and behavioral levels.

scholarly journals A non-coding indel polymorphism in the fruitless gene of Drosophila melanogaster exhibits antagonistically pleiotropic fitness effects

2020 ◽  
Author(s):  
Michael D. Jardine ◽  
Filip Ruzicka ◽  
Charlotte Diffley ◽  
Kevin Fowler ◽  
Max Reuter
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Balancing Selection ◽  
The Other ◽  
Antagonistic Pleiotropy ◽  
Indel Polymorphism ◽  
Fitness Components ◽  
Fitness Effects ◽  
Males And Females ◽  
Opposing Effects

AbstractThe amount of genetic variation for fitness within populations tends to exceed that expected under mutation-selection-drift balance. Several mechanisms have been proposed to actively maintain polymorphism and account for this discrepancy, including antagonistic pleiotropy (AP), where allelic variants have opposing effects on different components of fitness. Here we identify a non-coding indel polymorphism in the fruitless gene of Drosophila melanogaster and measure survival and reproductive components of fitness in males and females of replicate lines carrying one or the other allele. Expressing the fruitless region in a hemizygous state we observe a pattern of AP, with one allele resulting in greater reproductive fitness while the other confers greater survival to adulthood. Different fitness effects were observed in an alternative genetic background, suggesting widespread epistatic effects. Our findings link sequence-level variation at a single locus with complex effects on a range of fitness components, thus helping to explain the maintenance of genetic variation for fitness. Transcription factors, such as fruitless, may be prime candidates for targets of balancing selection since they interact with multiple target loci and their associated phenotypic effects.

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