scholarly journals Fitness effects but no temperature-mediated balancing selection at the polymorphic Adh gene of Drosophila melanogaster

2019 ◽  
Vol 116 (43) ◽  
pp. 21634-21640 ◽  
Author(s):  
Mohammad A. Siddiq ◽  
Joseph W. Thornton
Keyword(s):  
Drosophila Melanogaster ◽  
High Temperatures ◽  
Ethanol Tolerance ◽  
Balancing Selection ◽  
Demographic History ◽  
Transgenic Animals ◽  
Trade Off ◽  
Regulatory Variants ◽  
Adh Gene ◽  
Latitudinal Clines

Polymorphism in the alcohol dehydrogenase (ADH) protein of Drosophila melanogaster, like genetic variation in many other enzymes, has long been hypothesized to be maintained by a selective trade-off between thermostability and enzyme activity. Two major Adh variants, named Fast and Slow, are distributed along latitudinal clines on several continents. The balancing selection trade-off hypothesis posits that Fast is favored at high latitudes because it metabolizes alcohol faster, whereas Slow is favored at low latitudes because it is more stable at high temperatures. Here we use biochemical and physiological assays of precisely engineered genetic variants to directly test this hypothesis. As predicted, the Fast protein has higher catalytic activity than Slow, and both the Fast protein and regulatory variants linked to it confer greater ethanol tolerance on transgenic animals. But we found no evidence of a temperature-mediated trade-off: The Fast protein is not less stable or active at high temperatures, and Fast alleles increase ethanol tolerance and survivorship at all temperatures tested. Further, analysis of a population genomic dataset reveals no signature of balancing selection in the Adh gene. These results provide strong evidence against balancing selection driven by a stability/activity trade-off in Adh, and they justify caution about this hypothesis for other enzymes except those for which it has been directly tested. Our findings tentatively suggest that environment-specific selection for the Fast allele, coupled with demographic history, may have produced the observed pattern of Adh variation.

scholarly journals Corrigendum to: Demographic history of the human commensal Drosophila melanogaster

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
J Roman Arguello ◽  
Stefan Laurent ◽  
Andrew G Clark
Keyword(s):  
Drosophila Melanogaster ◽  
Demographic History ◽  
History Of

scholarly journals GENETIC DIFFERENTIATION BETWEEN GEOGRAPHICALLY DISTANT POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1982 ◽  
Vol 101 (2) ◽  
pp. 235-256
Author(s):  
Rama S Singh ◽  
Donal A Hickey ◽  
Jean David
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Differentiation ◽  
Gene Frequency ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Clinal Variation ◽  
Significant Genetic Differentiation ◽  
African Populations ◽  
Latitudinal Clines ◽  
North And South

ABSTRACT We have studied allozyme variation at 26 gene loci in nine populations of Drosophila melanogaster originating on five different continents. The distant populations show significant genetic differentiation. However, only half of the loci studied have contributed to this differentiation; the other half show identical patterns in all populations. The genetic differentiation in North American, European and African populations is correlated with the major climatic differences between north and south. These differences arise mainly from seven loci that show gene-frequency patterns suggestive of latitudinal clines in allele frequencies. The clinal variation is such that subtropical populations are more heterozygous than temperate populations. These results are discussed in relation to the selectionist and neutralist hypotheses of genetic variation in natural populations.

scholarly journals Repeated stress exposure results in a survival–reproduction trade-off in Drosophila melanogaster

2009 ◽  
Vol 277 (1683) ◽  
pp. 963-969 ◽  
Author(s):  
Katie E. Marshall ◽  
Brent J. Sinclair
Keyword(s):  
Drosophila Melanogaster ◽  
Model Organism ◽  
Intrinsic Rate ◽  
Intrinsic Rate Of Increase ◽  
Stress Exposure ◽  
Trade Off ◽  
Repeated Stress ◽  
Rate Of Increase ◽  
In The Wild ◽  
Future Reproduction

While insect cold tolerance has been well studied, the vast majority of work has focused on the effects of a single cold exposure. However, many abiotic environmental stresses, including temperature, fluctuate within an organism's lifespan. Given that organisms may trade-off survival at the cost of future reproduction, we investigated the effects of multiple cold exposures on survival and fertility in the model organism Drosophila melanogaster . We found that multiple cold exposures significantly decreased mortality compared with the same length of exposure in a single sustained bout, but significantly decreased fecundity (as measured by r , the intrinsic rate of increase) as well, owing to a shift in sex ratio. This change was reflected in a long-term decrease in glycogen stores in multiply exposed flies, while a brief effect on triglyceride stores was observed, suggesting flies are reallocating energy stores. Given that many environments are not static, this trade-off indicates that investigating the effects of repeated stress exposure is important for understanding and predicting physiological responses in the wild.

scholarly journals Cross-Species RNAi Rescue Platform in Drosophila melanogaster

Genetics ◽  
2009 ◽  
Vol 183 (3) ◽  
pp. 1165-1173 ◽  
Author(s):  
Shu Kondo ◽  
Matthew Booker ◽  
Norbert Perrimon
Keyword(s):  
Cell Culture ◽  
Drosophila Melanogaster ◽  
Large Scale ◽  
Transgenic Animals ◽  
Selection Marker ◽  
Bacterial Artificial Chromosomes ◽  
Loss Of Function ◽  
Artificial Chromosomes ◽  
Target Effects

RNAi-mediated gene knockdown in Drosophila melanogaster is a powerful method to analyze loss-of-function phenotypes both in cell culture and in vivo. However, it has also become clear that false positives caused by off-target effects are prevalent, requiring careful validation of RNAi-induced phenotypes. The most rigorous proof that an RNAi-induced phenotype is due to loss of its intended target is to rescue the phenotype by a transgene impervious to RNAi. For large-scale validations in the mouse and Caenorhabditis elegans, this has been accomplished by using bacterial artificial chromosomes (BACs) of related species. However, in Drosophila, this approach is not feasible because transformation of large BACs is inefficient. We have therefore developed a general RNAi rescue approach for Drosophila that employs Cre/loxP-mediated recombination to rapidly retrofit existing fosmid clones into rescue constructs. Retrofitted fosmid clones carry a selection marker and a phiC31 attB site, which facilitates the production of transgenic animals. Here, we describe our approach and demonstrate proof-of-principle experiments showing that D. pseudoobscura fosmids can successfully rescue RNAi-induced phenotypes in D. melanogaster, both in cell culture and in vivo. Altogether, the tools and method that we have developed provide a gold standard for validation of Drosophila RNAi experiments.

scholarly journals Absence of reproduction-immunity trade-off in male Drosophila melanogaster evolving under differential sexual selection

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Zeeshan Ali Syed ◽  
Vanika Gupta ◽  
Manas Geeta Arun ◽  
Aatashi Dhiman ◽  
Bodhisatta Nandy ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Trade Off

scholarly journals Selection for Ethanol Tolerance in Two Populations of Drosophila Melanogaster Segregating Alcohol Dehydrogenase Allozymes

1979 ◽  
Vol 32 (3) ◽  
pp. 387 ◽  
Author(s):  
John B Gibson ◽  
NigeI Lewis ◽  
MichaeI Adena ◽  
Susan R Wilson
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Ethanol Tolerance ◽  
Selection For ◽  
Two Populations

Selection for ethanol tolerance was equally successful in two populations of D. melanogaster in both of which the frequency of AdhF was 0�5 at the start of the experiment.

scholarly journals THE ALCOHOL DEHYDROGENASE POLYMORPHISM IN POPULATIONS OF DROSOPHILA MELANOGASTER. I. SELECTION IN DIFFERENT ENVIRONMENTS

Genetics ◽  
1978 ◽  
Vol 90 (1) ◽  
pp. 161-191
Author(s):  
W van Delden ◽  
A C Boerema ◽  
A Kamping
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Experimental Evidence ◽  
Balancing Selection ◽  
Adult Survival ◽  
High Survival ◽  
High Humidity ◽  
Allozyme Polymorphism ◽  
Degree Of Dominance ◽  
Frequency Changes

ABSTRACT The allozyme polymorphism at the alcohol dehydrogenase locus in Drosophila melanogaster was studied in order to obtain experimental evidence about the maintenance of this polymorphism. Populations started with different initial allele frequencies from homozygous F and S lines showed a convergence of frequencies on regular food at 25°, leading to values equal to those in the base populations. These results were interpreted as due to some kind of balancing selection. In populations kept at 29.8°, a lower equilibrium F frequency was attained. Addition of ethanol and some other alcohols to the food gave a rapid increase in F frequency, and high humidity decreased the F frequency slightly. Combination or alternation of ethanol and high humidity had variable effects in the populations tested. For a further analysis of the allele-frequency changes, estimates were obtained for egg-to-adult survival under different conditions and for adult survival on ethanol-supplemented food. On ethanol food (both at regular and high humidity), egg-to-adult survival of SS homozygotes was considerably lower than that of the FF and FS genotypes. Under regular conditions of food, temperature and humidity, a tendency to heterozygote superiority was observed, while at high humidity a relative high survival of SS was noticed in some tests. Adult survival of SS was lower than that of FF, but FS was generally intermediate, though the degree of dominance differed between populations. The results are consistent with the hypothesis of the occurrence of selection at the Adh locus.

scholarly journals Recurrent Collection of Drosophila melanogaster from Wild African Environments and Genomic Insights into Species History

2019 ◽  
Vol 37 (3) ◽  
pp. 627-638 ◽  
Author(s):  
Quentin D Sprengelmeyer ◽  
Suzan Mansourian ◽  
Jeremy D Lange ◽  
Daniel R Matute ◽  
Brandon S Cooper ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Demographic History ◽  
Central Africa ◽  
Model Organism ◽  
Sub Saharan Africa ◽  
Wilderness Areas ◽  
Southern Central ◽  
History Of ◽  
Sub Saharan ◽  
Improved Model

Abstract A long-standing enigma concerns the geographic and ecological origins of the intensively studied vinegar fly, Drosophila melanogaster. This globally distributed human commensal is thought to originate from sub-Saharan Africa, yet until recently, it had never been reported from undisturbed wilderness environments that could reflect its precommensal niche. Here, we document the collection of 288 D. melanogaster individuals from multiple African wilderness areas in Zambia, Zimbabwe, and Namibia. The presence of D. melanogaster in these remote woodland environments is consistent with an ancestral range in southern-central Africa, as opposed to equatorial regions. After sequencing the genomes of 17 wilderness-collected flies collected from Kafue National Park in Zambia, we found reduced genetic diversity relative to town populations, elevated chromosomal inversion frequencies, and strong differences at specific genes including known insecticide targets. Combining these genomes with existing data, we probed the history of this species’ geographic expansion. Demographic estimates indicated that expansion from southern-central Africa began ∼13,000 years ago, with a Saharan crossing soon after, but expansion from the Middle East into Europe did not begin until roughly 1,800 years ago. This improved model of demographic history will provide an important resource for future evolutionary and genomic studies of this key model organism. Our findings add context to the history of D. melanogaster, while opening the door for future studies on the biological basis of adaptation to human environments.

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