X-chromosomal heterosis in Drosophila melanogaster

SUMMARYPopulation cages were set up containing an X-chromosome balancer, and either a single wild-type chromosome(homozygous cages) or a mixture of wild-type chromosomes(heterozygous cages). The balancer chromosome was eliminated more rapidly from the heterozygous cages, indicating that chromosome heterozygotes are at an advantage over chromosome homozygotes. The disadvantage of X-chromosome homozygosity in the female is estimated to be about 40%. From earlier studies it is known that the average disadvantage of homozygosity for either of the two major autosomes of D. melanogaster is approximately 80%. Since these autosomes are both about twice as long as the X chromosome, the disadvantage per unit length is similar for both chromosomal types.Both X-chromosomal and autosomal heterosis can be explained by either dominance or overdominance at individual loci. However, a dominance model can only explain the similarity if many of the X-linked loci (about 50%) are limited in expression to the female.

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An estimate of heterosis in Drosophila melanogaster

Genetics Research ◽

10.1017/s0016672300012453 ◽

1971 ◽

Vol 18 (1) ◽

pp. 97-105 ◽

Cited By ~ 54

Author(s):

J. A. Sved

Keyword(s):

Drosophila Melanogaster ◽

High Frequency ◽

Marker Chromosome ◽

Selective Advantage ◽

Wild Type ◽

Set Up

SUMMARYTwenty-five population cages of D. melanogaster were set up, each containing a different wild-type second chromosome and the marker chromosome Cy. In all but one case where contamination apparently occurred, the Cy chromosome persisted in the population at high frequency, showing a selective advantage of Cy/ + heterozygotes over wild-type homozygotes. Overall, the results indicate that homozygosity of the entire second chromosome causes a depression in fitness of the order of 85%.

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Can chromosomal heterosis in Drosophila be explained by deleterious recessive genes? Negative results from a dichromosomal population test

Genetics Research ◽

10.1017/s0016672300028019 ◽

1989 ◽

Vol 53 (2) ◽

pp. 129-140 ◽

Cited By ~ 4

Author(s):

Alan N. Wilton ◽

Michael G. Joseph ◽

John A. Sved

Keyword(s):

Selection Intensity ◽

Wild Type ◽

Partial Dominance ◽

Negative Results ◽

Rate Of Increase ◽

Recessive Genes ◽

Set Up ◽

Expected Increase ◽

Balancer Chromosome ◽

Rule Out

SummaryHigh levels of chromosomal heterosis have previously been detected in Drosophila using the balancer chromosome equilibration (BE) technique, in which single wild-type chromosomes are introduced into population cages along with a dominant/lethal balancer chromosome. The balancer chromosome is rarely eliminated in such populations, showing that the fitness of chromosome homozygotes must be low by comparison with chromosomal heterozygotes. As with all cases of chromosomal heterosis, the underlying cause could either be deleterious recessives at various loci or generalized overdominance. The experiment of the present paper examines the first of these explanations. Population cages containing just two wild-type chromosomes (dichromosomal populations) were set up and allowed to run for many generations. Single chromosomes were then re-extracted from these populations, and their fitness measured using the BE technique. Our expectation was that the gradual elimination of recessive genes from the dichromosomal populations ought to result in an increase in the fitness of such re-extracted chromosome homozygotes. Yet in two replicated experiments we were unable to demonstrate an; unequivocal increase in fitness. We have estimated the rate of increase of fitness under multiple locus dominance and partial dominance models. The principal unknown parameter in these calculations is the selection intensity per locus, s. The expected increase is approximately proportional to s, and we estimate that values of s around 1/64 should be detectable in our experiments. However linkage is expected to reduce the efficiency of the dichromosomal procedure We show by computer simulation that this reduction is by a factor of approximately 2, thus increasing the detectable level of s to approximately 1/32. Consideration of mutation-selection balance models shows that this is a feasible selection intensity only if dominance is nearly complete. Thus we are unable to rule out the notion that the genes responsible for heterosis are maintained by a simple mutation-selection balance, but the experimental results constrain the parameters of such a model to a narrow range.

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The Triplo-lethal locus of Drosophila: reexamination of mutants and discovery of a second-site suppressor.

Genetics ◽

10.1093/genetics/141.3.1037 ◽

1995 ◽

Vol 141 (3) ◽

pp. 1037-1042 ◽

Cited By ~ 1

Author(s):

D R Dorer ◽

D H Ezekiel ◽

A C Christensen

Keyword(s):

Drosophila Melanogaster ◽

Single Locus ◽

Wild Type ◽

Recessive Lethal ◽

Hypomorphic Alleles ◽

Type Chromosome

Abstract In the genome of Drosophila melanogaster there is a single locus, Triplo-lethal (Tpl), that causes lethality when present in either one or three copies in an otherwise diploid animal. Previous attempts to mutagenize Tpl produced alleles that were viable over a chromosome bearing a duplication of Tpl, but were not lethal in combination with a wild-type chromosome, as deficiencies for Tpl are. These mutations were interpreted as hypomorphic alleles of Tpl. In this work, we show that these alleles are not mutations at Tpl; rather, they are dominant mutations in a tightly linked, but cytologically distant, locus that we have named Suppressor-of-Tpl (Sul(Tpl)). Su(Tpl) mutations suppress the lethality associated with three copies of the Triplo-lethal locus and are recessive lethal. We have mapped Su(Tpl) to the approximate map position 3-46.5, within the cytological region 76B-76D.

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High levels of fitness modifiers induced by hybrid dysgenesis in Drosophila melanogaster

Genetics Research ◽

10.1017/s0016672300024800 ◽

1986 ◽

Vol 48 (2) ◽

pp. 89-94 ◽

Cited By ~ 35

Author(s):

Benjamin J. Fitzpatrick ◽

John A. Sved

Keyword(s):

Drosophila Melanogaster ◽

Hybrid Dysgenesis ◽

Wild Type ◽

Homozygous Condition ◽

Single Generation ◽

Balancer Chromosome ◽

Visible Mutation

SummaryWild-type chromosomes of D. melanogaster mutagenized by passage through a single generation of hybrid dysgenesis have been compared against identical chromosomes passed through a reciprocal, non-dysgenic cross. Fitness of the chromosome in homozygous condition has been examined in population cages using the technique of balancer chromosome equilibration. The results indicate that amongst chromosomes with no lethal or visible mutation, more than 50% have suffered a measurable decline in fitness. The magnitude of this decline is estimated to be in the range 10–20%.

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ON THE POLYTENE MORPHOLOGY OF A DROSOPHILA MELANOGASTER CHROMOSOMAL INVERSION INCLUDING THE NUCLEOLUS ORGANIZER

Canadian Journal of Genetics and Cytology ◽

10.1139/g77-068 ◽

1977 ◽

Vol 19 (4) ◽

pp. 637-644 ◽

Cited By ~ 3

Author(s):

David Nash ◽

E. R. Vyse

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Nucleolus Organizer ◽

Chromosomal Inversion ◽

Wild Type ◽

Polytene Nuclei ◽

Type Chromosome

In (1) 1625 inverts about 80% of the polytene X-chromosome of Drosophila melanogaster, including the nucleolus organizer. The nucleolus is found associated with the new nucleolus organizer position in polytene nuclei. In this respect, it appears that the nucleolus has a definitive association with a specific segment of the polytene X-chromosome. However, it is not possible to suggest an association with a specific chromomere; nor is polytene material generated from positions normally proximal to the nucleolus organizer routinely recognizable in the inverted chromosome. A single, exceptional nucleus containing uninverted basal polytene material (which, hence, should have its origin from a position proximal to the nucleolus organizer in a wild-type chromosome) suggests that polytenization in basal heterochromatin may occur, but rarely.

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

Genetics ◽

10.1093/genetics/143.3.1339 ◽

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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Production and scavenging of reactive oxygen species both affect reproductive success in male and female Drosophila melanogaster

Biogerontology ◽

10.1007/s10522-021-09922-1 ◽

2021 ◽

Author(s):

Biz R. Turnell ◽

Luisa Kumpitsch ◽

Klaus Reinhardt

Keyword(s):

Reactive Oxygen Species ◽

Drosophila Melanogaster ◽

Reactive Oxygen ◽

Cellular Aging ◽

Ros Production ◽

Oxygen Species ◽

Wild Type ◽

Ros Scavenging ◽

Respiratory Pathway ◽

Male And Female

AbstractSperm aging is accelerated by the buildup of reactive oxygen species (ROS), which cause oxidative damage to various cellular components. Aging can be slowed by limiting the production of mitochondrial ROS and by increasing the production of antioxidants, both of which can be generated in the sperm cell itself or in the surrounding somatic tissues of the male and female reproductive tracts. However, few studies have compared the separate contributions of ROS production and ROS scavenging to sperm aging, or to cellular aging in general. We measured reproductive fitness in two lines of Drosophila melanogaster genetically engineered to (1) produce fewer ROS via expression of alternative oxidase (AOX), an alternative respiratory pathway; or (2) scavenge fewer ROS due to a loss-of-function mutation in the antioxidant gene dj-1β. Wild-type females mated to AOX males had increased fecundity and longer fertility durations, consistent with slower aging in AOX sperm. Contrary to expectations, fitness was not reduced in wild-type females mated to dj-1β males. Fecundity and fertility duration were increased in AOX and decreased in dj-1β females, indicating that female ROS levels may affect aging rates in stored sperm and/or eggs. Finally, we found evidence that accelerated aging in dj-1β sperm may have selected for more frequent mating. Our results help to clarify the relative roles of ROS production and ROS scavenging in the male and female reproductive systems.

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INTRACISTRONIC MAPPING OF ELECTROPHORETIC SITES IN DROSOPHILA MELANOGASTER: FIDELITY OF INFORMATION TRANSFER BY GENE CONVERSION

Genetics ◽

10.1093/genetics/76.2.289 ◽

1974 ◽

Vol 76 (2) ◽

pp. 289-299

Author(s):

Margaret McCarron ◽

William Gelbart ◽

Arthur Chovnick

Keyword(s):

Drosophila Melanogaster ◽

Information Transfer ◽

Large Scale ◽

Genetic Basis ◽

Xanthine Dehydrogenase ◽

Specific Protein ◽

Wild Type ◽

Electrophoretic Variation ◽

The Stability ◽

Recombination Experiments

ABSTRACT A convenient method is described for the intracistronic mapping of genetic sites responsible for electrophoretic variation of a specific protein in Drosophila melanogaster. A number of wild-type isoalleles of the rosy locus have been isolated which are associated with the production of electrophoretically distinguishable xanthine dehydrogenases. Large-scale recombination experiments were carried out involving null enzyme mutants induced on electrophoretically distinct wild-type isoalleles, the genetic basis for which is followed as a nonselective marker in the cross. Additionally, a large-scale recombination experiment was carried out involving null enzyme rosy mutants induced on the same wild-type isoallele. Examination of the electrophoretic character of crossover and convertant products recovered from the latter experiment revealed that all exhibited the same parental electrophoretic character. In addition to documenting the stability of the xanthine dehydrogenase electrophoretic character, this observation argues against a special mutagenesis hypothesis to explain conversions resulting from allele recombination studies.

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Somatic production of reactive oxygen species does not predict its production in sperm cells across Drosophila melanogaster lines

BMC Research Notes ◽

10.1186/s13104-021-05550-7 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Biz R. Turnell ◽

Luisa Kumpitsch ◽

Anne-Cécile Ribou ◽

Klaus Reinhardt

Keyword(s):

Reactive Oxygen Species ◽

Drosophila Melanogaster ◽

Reactive Oxygen ◽

Future Research ◽

Ros Production ◽

Oxygen Species ◽

Loss Of Function ◽

Wild Type ◽

Ros Scavenging ◽

Transport Chain

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.

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Quantitative investigation reveals distinct phases in Drosophila sleep

Communications Biology ◽

10.1038/s42003-021-01883-y ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Xiaochan Xu ◽

Wei Yang ◽

Binghui Tian ◽

Xiuwen Sui ◽

Weilai Chi ◽

...

Keyword(s):

Drosophila Melanogaster ◽

General Pattern ◽

Model Organism ◽

Infrared Camera ◽

Fruit Fly ◽

Genetic Dissection ◽

Power Law Distribution ◽

Quantitative Investigation ◽

Waking Up ◽

Set Up

AbstractThe fruit fly, Drosophila melanogaster, has been used as a model organism for the molecular and genetic dissection of sleeping behaviors. However, most previous studies were based on qualitative or semi-quantitative characterizations. Here we quantified sleep in flies. We set up an assay to continuously track the activity of flies using infrared camera, which monitored the movement of tens of flies simultaneously with high spatial and temporal resolution. We obtained accurate statistics regarding the rest and sleep patterns of single flies. Analysis of our data has revealed a general pattern of rest and sleep: the rest statistics obeyed a power law distribution and the sleep statistics obeyed an exponential distribution. Thus, a resting fly would start to move again with a probability that decreased with the time it has rested, whereas a sleeping fly would wake up with a probability independent of how long it had slept. Resting transits to sleeping at time scales of minutes. Our method allows quantitative investigations of resting and sleeping behaviors and our results provide insights for mechanisms of falling into and waking up from sleep.

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