scholarly journals Gut cancer increases the risk for Drosophila to be preyed upon by hunting spiders

2020 ◽  
Author(s):  
David Duneau ◽  
Nicolas Buchon
Keyword(s):  
Colon Cancer ◽  
Drosophila Melanogaster ◽  
Chronic Infection ◽  
Selective Pressure ◽  
Selective Predation ◽  
Wolf Spiders ◽  
Providencia Rettgeri ◽  
Jumping Spiders ◽  
Invertebrate Species ◽  
In The Wild

AbstractPredators are thought to prey on individuals that are in poor physical condition, although the evidence supporting this is ambiguous. We tested if sick individuals where more predated using Drosophila melanogaster flies as manipulable preys. We asked whether hunting spiders, trapped from the wild, would selectively prey upon flies with compromised health (i.e. chronically infected or cancerous) versus healthy flies under laboratory conditions. Flies chronically infected with the bacterium Providencia rettgeri, a natural Drosophila pathogen, were not selectively preyed upon by neither jumping spiders, nor small wolf spiders. We suggest that this result support the hypothesis that chronic infection is associated with reduced symptoms notably to avoid the predation of their host. We then induced colon cancer in some of the flies and asked whether the presence of cancer led to selective predation; there is little evidence for this, even in vertebrates. As the cancer developed, the incidence of predation by jumping spiders on the afflicted flies increased. We conclude that disease can have different lethal consequences through predation, even in invertebrate species, and that cancer is a factor in selective predation. Our results may explain why early tumors, but not metastasized cancers, are commonly detected in organisms in the wild, as cancer bearing individuals are rapidly eliminated due to the strong selective pressure against them.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

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 Kill and cure: dietary augmentation of immune defences against colon cancer

2000 ◽  
Vol 59 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Fiona Armstrong ◽  
J. C. Mathers
Keyword(s):  
Colon Cancer ◽  
Immune System ◽  
Genetic Disease ◽  
Selective Pressure ◽  
Transformed Cells ◽  
Tumour Suppressor Genes ◽  
Food Components ◽  
Immune Attack ◽  
Dietary Components ◽  
Immune Defences

At its most fundamental, cancer is a genetic disease resulting from inherited or acquired mutations in tumour suppressor genes and proto-oncogenes. Environmental factors, including ingested food components, interact with genetic inheritance to determine individual cancer risk. There is growing evidence that the immune system exerts selective pressure during neoplastic development. Tumour cells that evade this immunosurveillance because they are non-antigenic or because they defend themselves successfully against immune attack have a survival advantage. Effective chemopreventative agents will include dietary components that enhance the immune system’s ability to identify transformed cells and to target them for apoptosis.

scholarly journals REPRODUCTION IN CAGE POPULATIONS OF A POLYMORPHISM REGULARLY OBSERVED IN THE NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER IN FRANCE

Genetics ◽  
1978 ◽  
Vol 88 (4) ◽  
pp. 755-759
Author(s):  
Annie Fleuriet
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Rate Of Return ◽  
Rapid Rate ◽  
Experimental Conditions ◽  
Co2 Sensitivity ◽  
In The Wild ◽  
Strong Forces

ABSTRACT Polymorphism for both alleles of a gene ref(2)P, which is a usual trait of French natural populations of Drosophila melanogaster, can be reproduced in experimental conditions. ref(2)P is a gene for resistance to the hereditary, noncontagious Rhabdovirus α, responsible for CO2 sensitivity in Drosophila melanogaster. The equilibrium frequencies observed in cages are the same as in the wild, whether α virus is present or not. The rapid rate of return to these equilibrium frequencies indicates that strong forces, which remain to be determined, are responsible for the maintenance of this polymorphism.

The development of the sensory neuron pattern in the antennal disc of wild-type and mutant (lz3, ssa) Drosophila melanogaster

Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 1063-1075
Author(s):  
M.C. Lienhard ◽  
R.F. Stocker
Keyword(s):  
Drosophila Melanogaster ◽  
Sensory Neuron ◽  
Antennal Segment ◽  
Wild Type ◽  
Homeotic Mutant ◽  
In The Wild ◽  
The Brain ◽  
Antennal Disc ◽  
Antennal Nerve

The development of the sensory neuron pattern in the antennal disc of Drosophila melanogaster was studied with a neuron-specific monoclonal antibody (22C10). In the wild type, the earliest neurons become visible 3 h after pupariation, much later than in other imaginal discs. They lie in the center of the disc and correspond to the neurons of the adult aristal sensillum. Their axons join the larval antennal nerve and seem to establish the first connection towards the brain. Later on, three clusters of neurons appear in the periphery of the disc. Two of them most likely give rise to the Johnston's organ in the second antennal segment. Neurons of the olfactory third antennal segment are formed only after eversion of the antennal disc (clusters t1-t3). The adult pattern of antennal neurons is established at about 27% of metamorphosis. In the mutant lozenge3 (lz3), which lacks basiconic antennal sensilla, cluster t3 fails to develop. This indicates that, in the wild type, a homogeneous group of basiconic sensilla is formed by cluster t3. The possible role of the lozenge gene in sensillar determination is discussed. The homeotic mutant spineless-aristapedia (ssa) transforms the arista into a leg-like tarsus. Unlike leg discs, neurons are missing in the larval antennal disc of ssa. However, the first neurons differentiate earlier than in normal antennal discs. Despite these changes, the pattern of afferents in the ectopic tarsus appears leg specific, whereas in the non-transformed antennal segments a normal antennal pattern is formed. This suggests that neither larval leg neurons nor early aristal neurons are essential for the outgrowth of subsequent afferents.

Consequences of elevated CO2 exposure across multiple life stages in a coastal forage fish

2016 ◽  
Vol 74 (4) ◽  
pp. 1051-1061 ◽  
Author(s):  
Christopher S. Murray ◽  
Lee A. Fuiman ◽  
Hannes Baumann
Keyword(s):  
Elevated Co2 ◽  
Condition Factor ◽  
Length Distribution ◽  
Life Stages ◽  
Menidia Menidia ◽  
Selective Predation ◽  
High Co2 ◽  
Atlantic Silverside ◽  
In The Wild ◽  
Exposure Experiment

Ocean acidification may impact the fitness of marine fish, however, studies reporting neutral to moderate effects have mostly performed short-term exposures to elevated CO2, whereas longer-term studies across life stages are still scarce. We performed a CO2 exposure experiment, in which a large number (n > 2200) of Atlantic silverside Menidia menidia offspring from wild spawners were reared for 135 days through their embryonic, larval, and juvenile stages under control (500 µatm) and high CO2 conditions (2300 µatm). Although survival was high across treatments, subtle but significant differences in length, weight, condition factor and fatty acid (FA) composition were observed. On average, fish from the acidified treatment were 4% shorter and weighed 6% less, but expressed a higher condition factor than control juveniles. In addition, the metrics of length and weight distributions differed significantly, with juveniles from the high CO2 treatment occupying more extreme size classes and the length distribution shifting to a positive kurtosis. Six of twenty-seven FAs differed significantly between treatments. Our results suggest that high CO2 conditions alter long-term growth in M. menidia, particularly in the absence of excess food. It remains to be shown whether and how these differences will impact fish populations in the wild facing size-selective predation and seasonally varying prey abundance.

scholarly journals Aquaporins in the wild: natural genetic diversity and selective pressure in the PIP gene family in five Neotropical tree species

2010 ◽  
Vol 10 (1) ◽  
pp. 202 ◽  
Author(s):  
Delphine Audigeos ◽  
Anna Buonamici ◽  
Laurent Belkadi ◽  
Paul Rymer ◽  
David Boshier ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Family ◽  
Tree Species ◽  
Selective Pressure ◽  
Neotropical Tree ◽  
In The Wild

scholarly journals The abnormal oocyte phenotype is correlated with the presence of blood transposon in Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 123 (3) ◽  
pp. 485-494
Author(s):  
G Lavorgna ◽  
C Malva ◽  
A Manzi ◽  
S Gigliotti ◽  
F Graziani
Keyword(s):  
Drosophila Melanogaster ◽  
Sequence Analysis ◽  
Restriction Enzyme ◽  
Polymorphism Analysis ◽  
Restriction Map ◽  
Dna Rearrangement ◽  
Restriction Enzyme Site ◽  
Wild Type ◽  
Chromosome Walking ◽  
In The Wild

Abstract The abnormal oocyte mutation (2;44) originates in the wild: it confers no visible phenotype on homozygous abo males or females, but homozygous abo females produce defective eggs and the probability of their developing into adults is much lower than that of heterozygous sister females. We isolated by chromosome walking 200 kb of DNA from region 32. This paper reports that a restriction enzyme site polymorphism analysis in wild type and mutant stocks allowed us to identify a DNA rearrangement present only in stocks carrying the abo mutation. The rearrangement is caused by a DNA insert on the abo chromosome in region 32E which, by restriction map and sequence analysis, was identified as copia-like blood transposon. The transposon, in strains that had remained in abo homozygous conditions for several generations and had lost the abo maternal-effect, was no longer present in region 32E. Certain features of the abo mutation, discussed in the light of this finding, may be ascribed to the nature of the particular allele studied.

scholarly journals Linkage disequilibrium in natural and experimental populations of Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 120 (4) ◽  
pp. 1043-1051
Author(s):  
Z Smit-McBride ◽  
A Moya ◽  
F J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Linkage Disequilibrium ◽  
Assay Method ◽  
Effective Population ◽  
Population Mixing ◽  
Locus Pair ◽  
Two Samples ◽  
In The Wild ◽  
Population Sizes ◽  
Experimental Populations

Abstract We have studied linkage disequilibrium in Drosophila melanogaster in two samples from a wild population and in four large laboratory populations derived from the wild samples. We have assayed four polymorphic enzyme loci, fairly closely linked in the third chromosome: Sod Est-6, Pgm, and Odh. The assay method used allows us to identify the allele associations separately in each of the two homologous chromosomes from each male sampled. We have detected significant linkage disequilibrium between two loci in 16.7% of the cases in the wild samples and in 27.8% of the cases in the experimental populations, considerably more than would be expected by chance alone. We have also found three-locus disequilibria in more instances than would be expected by chance. Some disequilibria present in the wild samples disappear in the experimental populations derived from them, but new ones appear over the generations. The effective population sizes required to generate the observed disequilibria by randomness range from 40 to more than 60,000 individuals in the natural population, depending on which locus pair is considered, and from 100 to more than 60,000 in the experimental populations. These population sizes are unrealistic; the fact that different locus-pairs yield disparate estimates within the same population argues against the likelihood that the disequilibria may have arisen as a consequence of population bottlenecks. Migration, or population mixing, cannot be excluded as the process generating the disequilibria in the wild samples, but can in the experimental populations. We conclude that linkage disequilibrium in these populations is most likely due to natural selection acting on the allozymes, or on loci very tightly linked to them.

scholarly journals Sterols as dietary markers for Drosophila melanogaster

2019 ◽  
Author(s):  
Oskar Knittelfelder ◽  
Elodie Prince ◽  
Susanne Sales ◽  
Eric Fritzsche ◽  
Thomas Wöhner ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Cold Acclimation ◽  
Lipid Membranes ◽  
Population Based ◽  
Sterol Composition ◽  
Molar Ratio ◽  
Shotgun Lipidomics ◽  
Organ Specific ◽  
In The Wild ◽  
Lipidome Analysis

AbstractDuring cold acclimation fruit flies switch their feeding from yeast to plant food, however there are no robust markers to monitor it in the wild. Drosophila melanogaster is a sterol auxotroph and relies on dietary sterols to produce lipid membranes, lipoproteins and molting hormones. We employed shotgun lipidomics to quantify eight major food sterols in total extracts of heads, female and male genital tracts of adult flies. We found that their sterol composition is dynamic and reflective of flies diet in an organ-specific manner. Season-dependent changes observed in the organs of wild-living flies suggested that the molar ratio between yeast (ergosterol, zymosterol) and plant (sitosterol, stigmasterol) sterols is a quantifiable, generic and unequivocal marker of their feeding behavior, including cold acclimation. It provides technically simpler and more contrast readout compared to the full lipidome analysis and is suitable for ecological and environmental population-based studies.

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