scholarly journals Assessing putative interlocus sexual conflict in Drosophila melanogaster using experimental evolution

2005 ◽  
Vol 272 (1576) ◽  
pp. 2029-2035 ◽  
Author(s):  
Andrew D Stewart ◽  
Edward H Morrow ◽  
William R Rice
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Conflict ◽  
Experimental Evolution ◽  
Large Body ◽  
Direct Costs ◽  
Empirical Prediction ◽  
Indirect Benefits ◽  
Almost All ◽  
Sexually Antagonistic Coevolution

The theoretical foundation of sexually antagonistic coevolution is that females suffer a net fitness cost through their interactions with males. The empirical prediction is that direct costs to female lifetime fecundity will exceed indirect benefits despite a possible increase in the genetic quality of offspring. Although direct costs of males have been repeatedly shown, to date no study has comprehensively tested whether females are compensated for this direct harm through indirect benefits. Here we use experimental evolution to show that a mutation giving Drosophila melanogaster females nearly complete resistance to the direct costs of male courtship and remating, but which also excluded almost all indirect benefits, is strongly favoured by selection. We estimated the selection coefficient favouring the resistance allele to be +20%. These results demonstrate that any indirect benefits that females accrued were not sufficient to counter-balance the direct costs of males, and reinforce a large body of past studies by verifying interlocus sexual conflict in this model system.

scholarly journals Assessing sexual conflict in the Drosophila melanogaster laboratory model system

2006 ◽  
Vol 361 (1466) ◽  
pp. 287-299 ◽  
Author(s):  
William R Rice ◽  
Andrew D Stewart ◽  
Edward H Morrow ◽  
Jodell E Linder ◽  
Nicole Orteiza ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Sexual Conflict ◽  
Graphical Model ◽  
Direct Costs ◽  
Model System ◽  
Laboratory Model ◽  
Laboratory Populations ◽  
Spatial Refuge ◽  
Sexually Antagonistic Coevolution

We describe a graphical model of interlocus coevolution used to distinguish between the interlocus sexual conflict that leads to sexually antagonistic coevolution, and the intrinsic conflict over mating rate that is an integral part of traditional models of sexual selection. We next distinguish the ‘laboratory island’ approach from the study of both inbred lines and laboratory populations that are newly derived from nature, discuss why we consider it to be one of the most fitting forms of laboratory analysis to study interlocus sexual conflict, and then describe four experiments using this approach with Drosophila melanogaster . The first experiment evaluates the efficacy of the laboratory model system to study interlocus sexual conflict by comparing remating rates of females when they are, or are not, provided with a spatial refuge from persistent male courtship. The second experiment tests for a lag-load in males that is due to adaptations that have accumulated in females, which diminish male-induced harm while simultaneously interfering with a male's ability to compete in the context of sexual selection. The third and fourth experiments test for a lag-load in females owing to direct costs from their interactions with males, and for the capacity for indirect benefits to compensate for these direct costs.

scholarly journals Sexual conflict and reproductive isolation in flies

2009 ◽  
Vol 5 (5) ◽  
pp. 697-699 ◽  
Author(s):  
D.J. Hosken ◽  
O.Y. Martin ◽  
S. Wigby ◽  
T. Chapman ◽  
D.J. Hodgson
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Isolation ◽  
Sexual Conflict ◽  
Experimental Evolution ◽  
Empirical Support ◽  
Isolation Index

Sexual conflict is predicted to generate more rapid reproductive isolation between larger populations. While there is some empirical support for this, the data are inconsistent and, additionally, there has been criticism of some of the evidence. Here we reanalyse two experimental-evolution datasets using an isolation index widely applied in the speciation literature. We find evidence for reproductive isolation through sexual conflict in Sepsis cynipsea , but not in Drosophila melanogaster , and this occurred to a greater degree in larger populations, which is consistent with previous findings.

scholarly journals Manipulation of feeding regime alters sexual dimorphism for lifespan and reduces sexual conflict in Drosophila melanogaster

2017 ◽  
Vol 284 (1854) ◽  
pp. 20170391 ◽  
Author(s):  
Elizabeth M. L. Duxbury ◽  
Wayne G. Rostant ◽  
Tracey Chapman
Keyword(s):  
Drosophila Melanogaster ◽  
Life History ◽  
Sexual Dimorphism ◽  
Sexual Conflict ◽  
Experimental Evolution ◽  
Fruit Fly ◽  
Developmental Time ◽  
Feeding Regime ◽  
Focal Female ◽  
Feeding Regimes

Sexual dimorphism for lifespan (SDL) is widespread, but poorly understood. A leading hypothesis, which we test here, is that strong SDL can reduce sexual conflict by allowing each sex to maximize its sex-specific fitness. We used replicated experimental evolution lines of the fruit fly, Drosophila melanogaster , which had been maintained for over 360 generations on either unpredictable ‘Random’ or predictable ‘Regular’ feeding regimes. This evolutionary manipulation of feeding regime led to robust, enhanced SDL in Random over control, Regular lines. Enhanced SDL was associated with a significant increase in the fitness of focal males, tested with wild-type (WT) females. This was due to sex-specific changes to male life history, manifested as increased early reproductive output and reduced survival. In contrast, focal female fitness, tested with WT males, did not differ across regimes. Hence increased SDL was associated with a reduction in sexual conflict, which increased male fitness and maintained fitness in females. Differences in SDL were not associated with developmental time or developmental survival. Overall, the results showed that the expression of enhanced SDL, resulting from experimental evolution of feeding regimes, was associated with male-specific changes in life history, leading to increased fitness and reduced sexual conflict.

Sexual selection affects the evolution of contact pheromones in Drosophila melanogaster populations isolated by differential sexual conflict

2019 ◽  
Author(s):  
Rochishnu Dutta ◽  
Tejinder Singh Chechi ◽  
N. G. Prasad
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Reproductive Isolation ◽  
Sexual Conflict ◽  
Population Differentiation ◽  
Lipid Profiles ◽  
Mate Preference ◽  
Cuticular Lipid ◽  
Antagonistic Coevolution ◽  
Sexually Antagonistic Coevolution

Abstract Background: The ability of sexual conflict to facilitate reproductive isolation is widely anticipated. However, very few experimental evolutionary studies have convincingly demonstrated the evolution of reproductive isolation due to sexual conflict. Recently a study on the replicates of Drosophila melanogaster populations under differential sexual conflict found that divergent mate preference evolved among replicates under high sexual conflict regime. The precopulatory isolating mechanism underlying such divergent mate preference could be sexual signals such as cuticular lipids since they evolve rapidly and are involved in D. melanogaster mate recognition. Using Drosophila melanogaster replicates used in the previous study, we investigate whether cuticular lipid divergence bears signatures of sexually antagonistic coevolution that led to reproductive isolation among replicates of high sexual conflict regime. Results: We found that their cuticular lipid profiles are sexually dimorphic. Although replicates with male biased sex ratio evolved isolation in reproductive traits due to high sexual conflict, the patterns of cuticular lipid divergence in high and low sexual conflict regimes suggest that sexual selection is the dominant selection pressure rather than sexual conflict affecting the cuticular lipid profile. We also find cuticular lipid divergence patterns to be suggestive of the Buridan’s Ass regime which is one of the six possible mechanism to resolve sexual conflict. Conclusions: Although reproductive isolation due to sexual conflict is anticipated, evolution of a sexually selected trait under sexual conflict may not lead to population differentiation in expected lines. This is because speciation due to sexually antagonistic coevolution is only one of the several outcomes of sexual conflict. This study indicates that population differentiation as a result of cuticular lipid divergence cannot be credited to sexual conflict despite high sexual conflict regime evolving divergent cuticular lipid profiles.

scholarly journals Reproductive Isolation through Experimental Manipulation of Sexually Antagonistic Coevolution in Drosophila melanogaster

2016 ◽  
Author(s):  
Syed Zeeshan Ali ◽  
Martik Chatterjee ◽  
Manas Arun Samant ◽  
Nagaraj Guru Prasad
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Isolation ◽  
Sexual Conflict ◽  
Evolutionary Model ◽  
Experimental Manipulation ◽  
Allopatric Populations ◽  
Antagonistic Coevolution ◽  
Before And After ◽  
Postmating Prezygotic Isolation ◽  
Sexually Antagonistic Coevolution

AbstractPromiscuity can drive the evolution of sexual conflict before and after mating occurs. Post-mating, the male ejaculate can selfishly manipulate female physiology leading to a chemical arms race between the sexes. Theory suggests that drift and sexually antagonistic coevolution can cause allopatric populations to evolve different chemical interactions between the sexes, thereby leading to postmating reproductive barriers and speciation. There is, however, little empirical evidence supporting this form of speciation. We tested this theory by creating an experimental evolutionary model of Drosophila melanogaster populations undergoing different levels of interlocus sexual conflict. We found that allopatric populations under elevated sexual conflict show assortative mating indicating premating reproductive isolation. Further, these allopatric populations also show reduced copulation duration and sperm defense ability when mating happens between individuals between individuals across populations compared to that within the same population, indicating postmating prezygotic isolation. Sexual conflict can cause reproductive isolation in allopatric populations through the coevolution of chemical (postmating prezygotic) as well as behavioural (premating) interaction between the sexes. Thus, to our knowledge, we provide the first comprehensive evidence of postmating (as well as premating) reproductive isolation due to sexual conflict.

Physicochemical and bacteriological characterization of hospital effluents and their impact on the environment

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Human Health ◽  
Fecal Coliforms ◽  
Chemical Pollution ◽  
Hospital Effluents ◽  
Biological Contaminants ◽  
Almost All ◽  
Direct Discharge ◽  
Significant Chemical

Liquid effluents discharged by hospitals may contain chemical and biological contaminants whose main source is the different substances used for the treatment of patients. This type of rejection can present a sanitary potentially dangerous risk for human health and can provoke a strong degradation of diverse environmental compartments mainly water and soils. The present study focuses on the quality of the liquid effluents of Hassani Abdelkader’s hospital of Sidi Bel-Abbes (West of Algeria). The results reveal a significant chemical pollution (COD: 879 mgO2/L, BOD5: 850 mgO2/L, NH4+ : 47.9 mg/l, NO2- : 4.2 mg/l, NO3- : 56.8 mg/l with respect to WHO standard of 90 mgO2/L, 30 mgO2/L, 0.5 mg/l, 1 mg/l and 1 mg/l respectively). However, these effluents are biodegradable since the ratio COD/BOD5 do not exceeded the value of 2 in almost all samples. The presence of pathogen germs is put into evidence such as pseudomonas, the clostridium, the staphylococcus, the fecal coliforms and fecal streptococcus. These results show that the direct discharge of these effluents constitutes a major threat to human health and the environment.

Cost-effectiveness of minimally invasive midline lumbar interbody fusion versus traditional open transforaminal lumbar interbody fusion

2020 ◽  
Vol 32 (1) ◽  
pp. 31-35
Author(s):  
Mladen Djurasovic ◽  
Jeffrey L. Gum ◽  
Charles H. Crawford ◽  
Kirk Owens ◽  
Morgan Brown ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Minimally Invasive ◽  
Interbody Fusion ◽  
Smoking Status ◽  
Transforaminal Lumbar Interbody Fusion ◽  
Direct Costs ◽  
Lumbar Interbody Fusion ◽  
Related Quality ◽  
Health Related

OBJECTIVEThe midline transforaminal lumbar interbody fusion (MIDLIF) using cortical screw fixation is a novel, minimally invasive procedure that may offer enhanced recovery over traditional open transforaminal lumbar interbody fusion (TLIF). Little information is available regarding the comparative cost-effectiveness of the MIDLIF over conventional TLIF. The purpose of this study was to compare cost-effectiveness of minimally invasive MIDLIF with open TLIF.METHODSFrom a prospective, multisurgeon, surgical database, a consecutive series of patients undergoing 1- or 2-level MIDLIF for degenerative lumbar conditions was identified and propensity matched to patients undergoing TLIF based on age, sex, smoking status, BMI, diagnosis, American Society of Anesthesiologists Physical Status Classification System (ASA) class, and levels fused. Direct costs at 1 year were collected, including costs associated with the index surgical visit as well as costs associated with readmission. Improvement in health-related quality of life was measured using EQ-5D and SF-6D.RESULTSOf 214 and 181 patients undergoing MIDLIF and TLIF, respectively, 33 cases in each cohort were successfully propensity matched. Consistent with propensity matching, there was no difference in age, sex, BMI, diagnosis, ASA class, smoking status, or levels fused. Spondylolisthesis was the most common indication for surgery in both cohorts. Variable direct costs at 1 year were $2493 lower in the MIDLIF group than in the open TLIF group (mean $15,867 vs $17,612, p = 0.073). There was no difference in implant (p = 0.193) or biologics (p = 0.145) cost, but blood utilization (p = 0.015), operating room supplies (p < 0.001), hospital room and board (p < 0.001), pharmacy (p = 0.010), laboratory (p = 0.004), and physical therapy (p = 0.009) costs were all significantly lower in the MIDLIF group. Additionally, the mean length of stay was decreased for MIDLIF as well (3.21 vs 4.02 days, p = 0.05). The EQ-5D gain at 1 year was 0.156 for MIDLIF and 0.141 for open TLIF (p = 0.821). The SF-6D gain at 1 year was 0.071 for MIDLIF and 0.057 for open TLIF (p = 0.551).CONCLUSIONSCompared with patients undergoing traditional open TLIF, those undergoing MIDLIF have similar 1-year gains in health-related quality of life, with total direct costs that are $2493 lower. Although the findings were not statistically significant, minimally invasive MIDLIF showed improved cost-effectiveness at 1 year compared with open TLIF.

Transformative Learning in Mastery-Oriented CS0 Course

2021 ◽  
pp. 234763112110072
Author(s):  
Srinivasan Lakshminarayanan ◽  
N. J. Rao ◽  
G. K. Meghana
Keyword(s):  
Transformative Learning ◽  
First Year ◽  
Guided Discovery ◽  
Engineering Programs ◽  
Transformative Experiences ◽  
Significant Difference ◽  
Cognitive Levels ◽  
Almost All ◽  
Core Course

The introductory programming course, commonly known as CS1 and offered as a core course in the first year in all engineering programs in India, is unique because it can address higher cognitive levels, metacognition and some aspects of the affective domain. It can provide much needed transformative experiences to students coming from a system of school education that is dominantly performance-driven. Unfortunately, the CS1 course, as practiced in almost all engineering programs, is also performance-driven because of a variety of compulsions. This paper suggests that the inclusion of a course CS0 can bring about transformative learning that can potentially make a significant difference in the quality of learning in all subsequent engineering courses. The suggested instruction design of this course takes the advantage of the unique features of a course in programming. The proposed CS0 course uses “extreme apprenticeship” and “guided discovery” methods of instruction. The effectiveness of these instruction methods was established through the use of the thematic analysis, a well-known qualitative research method, and the associated coding of transformative learning experiences and instruction components.

scholarly journals The hobo Transposable Element Excises and Has Related Elements in Tephritid Species

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1339-1347
Author(s):  
Alfred M Handler ◽  
Sheilachu P Gomez
Keyword(s):  
Drosophila Melanogaster ◽  
Ceratitis Capitata ◽  
Bactrocera Dorsalis ◽  
Parsimony Analysis ◽  
Wild Type ◽  
Anastrepha Suspensa ◽  
Tephritid Species ◽  
Mutant Strains ◽  
Almost All ◽  
Horizontal Transfers

Abstract Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays. Wild-type and mutant strains of Anastrepha suspensa, Bactrocera dorsalis, B. cucurbitae, Ceratitis capitata, and Toxotrypana curvicauda all supported hobo excision or deletion both in the presence and absence of co-injected hobo transposase, indicating a permissive state for hobo mobility and the existence of endogenous systems capable of mobilizing hobo. In several strains hobo helper reduced excision. Excision depended on hobo sequences in the indicator plasmid, though almost all excisions were imprecise and the mobilizing systems appear mechanistically different from hobo. hobe-related sequences were identified in all species except T. curvicauda. Parsimony analysis yielded a subgroup including the B. cucurbitae and C. capitata sequences along with hobo and Hermes, and a separate, more divergent subgroup including the A. suspensa and B. dorsalis sequences. All of the sequences exist as multiple genomic elements, and a deleted form of the B. cucurbitae element exists in B. dorsalis. The hobo-related sequences are probably members of the hAT transposon family with some evolving from distant ancestor elements, while others may have originated from more recent horizontal transfers.

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