scholarly journals Elevated levels of expression associated with regions of the Drosophila genome that lack crossing over

2008 ◽  
Vol 4 (6) ◽  
pp. 758-761 ◽  
Author(s):  
Penelope R Haddrill ◽  
Fergal M Waldron ◽  
Brian Charlesworth
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Molecular Evolution ◽  
Translational Efficiency ◽  
Crossing Over ◽  
Drosophila Genome ◽  
Deleterious Mutations ◽  
Fourth Chromosome ◽  
Genome Wide ◽  
Control Of Expression

The recombinational environment influences patterns of molecular evolution through the effects of Hill–Robertson interference. Here, we examine genome-wide patterns of gene expression with respect to recombinational environment in Drosophila melanogaster . We find that regions of the genome lacking crossing over exhibit elevated levels of expression, and this is most pronounced for genes on the entirely non-crossing over fourth chromosome. We find no evidence for differences in the patterns of gene expression between regions of high, intermediate and low crossover frequencies. These results suggest that, in the absence of crossing over, selection to maintain control of expression may be compromised, perhaps due to the accumulation of deleterious mutations in regulatory regions. Alternatively, higher gene expression may be evolving to compensate for defective protein products or reduced translational efficiency.

scholarly journals Inter- and Intraspecific Variation in Drosophila Genes with Sex-Biased Expression

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Lena Müller ◽  
Sonja Grath ◽  
Korbinian von Heckel ◽  
John Parsch
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Molecular Evolution ◽  
Protein Sequence ◽  
Sequence Variation ◽  
Purifying Selection ◽  
Sexually Dimorphic ◽  
Expression Divergence ◽  
Sexually Dimorphic Expression ◽  
Dimorphic Expression

Genes with sexually dimorphic expression (sex-biased genes) often evolve rapidly and are thought to make an important contribution to reproductive isolation between species. We examined the molecular evolution of sex-biased genes in Drosophila melanogaster and D. ananassae, which represent two independent lineages within the melanogaster group. We find that strong purifying selection limits protein sequence variation within species, but that a considerable fraction of divergence between species can be attributed to positive selection. In D. melanogaster, the proportion of adaptive substitutions between species is greatest for male-biased genes and is especially high for those on the X chromosome. In contrast, male-biased genes do not show unusually high variation within or between populations. A similar pattern is seen at the level of gene expression, where sex-biased genes show high expression divergence between species, but low divergence between populations. In D. ananassae, there is no increased rate of adaptation of male-biased genes, suggesting that the type or strength of selection acting on sex-biased genes differs between lineages.

scholarly journals Structural variants and selective sweep foci contribute to insecticide resistance in the Drosophila melanogaster genetic reference panel

2018 ◽  
Author(s):  
Paul Battlay ◽  
Llewellyn Green ◽  
Pontus B. Leblanc ◽  
Joshua M. Schmidt ◽  
Alexandre Fournier-Level ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Selective Sweep ◽  
Association Studies ◽  
Transcript Abundance ◽  
Reference Panel ◽  
Drosophila Genome ◽  
Genome Wide Association Studies ◽  
Genome Wide ◽  
Number Variation

AbstractPatterns of nucleotide polymorphism within populations of Drosophila melanogaster suggest that insecticides have been the selective agents driving the strongest recent bouts of positive selection. However, there is a need to explicitly link selective sweep loci to the particular insecticide phenotypes that could plausibly account for the drastic selective responses that are observed in these non-target insects. Here, we screen the Drosophila Genetic Reference Panel with two common insecticides; malathion (an organophosphate) and permethrin (a pyrethroid). Genome wide association studies map ‘survival-on-malathion’ to two of the largest sweeps in the D. melanogaster genome; Ace and Cyp6g1. Malathion survivorship also correlates with lines which have high levels of Cyp12d1 and Jheh1 and Jheh2 transcript abundance. Permethrin phenotypes map to the largest cluster of P450 genes in the Drosophila genome, however in contrast to a selective sweep driven by insecticide use, the derived state seems to be associated with susceptibility. These results underscore previous findings that highlight the importance of structural variation to insecticide phenotypes: Cyp6g1 exhibits copy number variation and transposable element insertions, Cyp12d1 is tandemly duplicated, the Jheh loci are associated with a Bari1 transposable element insertion, and a Cyp6a17 deletion is associated with susceptibility.

scholarly journals Genome-wide measurement of spatial expression in patterning mutants of Drosophila melanogaster

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 41 ◽  
Author(s):  
Peter A. Combs ◽  
Michael B. Eisen
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Early Embryo ◽  
Integrated Analysis ◽  
Spatial Patterning ◽  
Maternal Factors ◽  
Genome Wide ◽  
Binding Data ◽  
Complex Dependence ◽  
Blastoderm Stage

Patterning in the Drosophila melanogaster embryo is affected by multiple maternal factors, but the effect of these factors on spatial gene expression has not been systematically analyzed. Here we characterize the effect of the maternal factors Zelda, Hunchback and Bicoid by cryosectioning wildtype and mutant blastoderm stage embryos and sequencing mRNA from each slice. The resulting atlas of spatial gene expression highlights the intersecting roles of these factors in regulating spatial patterns, and serves as a resource for researchers studying spatial patterning in the early embryo. We identify a large number of genes with both expected and unexpected patterning changes, and through integrated analysis of transcription factor binding data identify common themes in genes with complex dependence on these transcription factors.

scholarly journals Phylogenetic Shifts in Gene Body Methylation Correlate with Gene Expression and Reflect Trait Conservation

2019 ◽  
Vol 37 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Danelle K Seymour ◽  
Brandon S Gaut
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Molecular Evolution ◽  
Methylation Status ◽  
Evolutionary Constraint ◽  
Gene Body ◽  
Gene Body Methylation ◽  
Plant Genomes ◽  
Genome Wide ◽  
Rates Of Molecular Evolution

Abstract A subset of genes in plant genomes are labeled with DNA methylation specifically at CG residues. These genes, known as gene-body methylated (gbM), have a number of associated characteristics. They tend to have longer sequences, to be enriched for intermediate expression levels, and to be associated with slower rates of molecular evolution. Most importantly, gbM genes tend to maintain their level of DNA methylation between species, suggesting that this trait is under evolutionary constraint. Given the degree of conservation in gbM, we still know surprisingly little about its function in plant genomes or whether gbM is itself a target of selection. To address these questions, we surveyed DNA methylation across eight grass (Poaceae) species that span a gradient of genome sizes. We first established that genome size correlates with genome-wide DNA methylation levels, but less so for genic levels. We then leveraged genomic data to identify a set of 2,982 putative orthologs among the eight species and examined shifts of methylation status for each ortholog in a phylogenetic context. A total of 55% of orthologs exhibited a shift in gbM, but these shifts occurred predominantly on terminal branches, indicating that shifts in gbM are rarely conveyed over time. Finally, we found that the degree of conservation of gbM across species is associated with increased gene length, reduced rates of molecular evolution, and increased gene expression level, but reduced gene expression variation across species. Overall, these observations suggest a basis for evolutionary pressure to maintain gbM status over evolutionary time.

scholarly journals Genome-Wide Gene Expression in relation to Age in Large Laboratory Cohorts of Drosophila melanogaster

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Kimberly A. Carlson ◽  
Kylee Gardner ◽  
Anjeza Pashaj ◽  
Darby J. Carlson ◽  
Fang Yu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Drosophila Melanogaster ◽  
Immune Function ◽  
Expression Patterns ◽  
Self Organizing Map ◽  
Control Of Gene Expression ◽  
Genome Wide ◽  
Complex Process ◽  
Temporal Variance ◽  
And Function

Aging is a complex process characterized by a steady decline in an organism’s ability to perform life-sustaining tasks. In the present study, two cages of approximately 12,000 mated Drosophila melanogaster females were used as a source of RNA from individuals sampled frequently as a function of age. A linear model for microarray data method was used for the microarray analysis to adjust for the box effect; it identified 1,581 candidate aging genes. Cluster analyses using a self-organizing map algorithm on the 1,581 significant genes identified gene expression patterns across different ages. Genes involved in immune system function and regulation, chorion assembly and function, and metabolism were all significantly differentially expressed as a function of age. The temporal pattern of data indicated that gene expression related to aging is affected relatively early in life span. In addition, the temporal variance in gene expression in immune function genes was compared to a random set of genes. There was an increase in the variance of gene expression within each cohort, which was not observed in the set of random genes. This observation is compatible with the hypothesis that D. melanogaster immune function genes lose control of gene expression as flies age.

scholarly journals Phylogenetic shifts in gene body methylation correlate with gene expression and reflect trait conservation

2019 ◽  
Author(s):  
Danelle K. Seymour ◽  
Brandon S. Gaut
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Molecular Evolution ◽  
Methylation Status ◽  
Evolutionary Constraint ◽  
Gene Body ◽  
Gene Body Methylation ◽  
Plant Genomes ◽  
Genome Wide ◽  
Rates Of Molecular Evolution

ABSTRACTA subset of genes in plant genomes are labeled with DNA methylation specifically at CG residues. These genes, known as gene-body methylated (gbM), have a number of associated characteristics. They tend to have longer sequences, to be enriched for intermediate expression levels, and to be associated with slower rates of molecular evolution. Most importantly, gbM genes tend to maintain their level of DNA methylation between species, suggesting that this trait is under evolutionary constraint. Given the degree of conservation in gbM, we still know surprisingly little about its function in plant genomes or whether gbM is itself a target of selection. To address these questions, we surveyed DNA methylation across eight grass (Poaceae) species that span a gradient of genome sizes. We first established that genome size correlates with genome-wide DNA methylation levels, but less so for genic levels. We then leveraged genomic data to identify a set of 2,982 putative orthologs among the eight species and examined shifts of methylation status for each ortholog in a phylogenetic context. A total of 55% of orthologs exhibited a shift in gbM, but these shifts occurred predominantly on terminal branches, indicating that shifts in gbM are rarely conveyed over time. Finally, we found that the degree of conservation of gbM across species is associated with increased gene length, reduced rates of molecular evolution, and increased gene expression level, but reduced gene expression variation across species. Overall, these observations suggest a basis for evolutionary pressure to maintain gbM status over evolutionary time.

scholarly journals RECOMBINATION AND DNA REPLICATION IN THE DROSOPHILA MELANOGASTER OOCYTE

Genetics ◽  
1973 ◽  
Vol 73 (1) ◽  
pp. 87-108
Author(s):  
Rhoda F Grell
Keyword(s):  
Drosophila Melanogaster ◽  
Dna Replication ◽  
Present Method ◽  
Sensitive Period ◽  
Crossing Over ◽  
Drosophila Genome ◽  
Chromosome 2

ABSTRACT A method is described that permits the recovery of a well-synchronized population of oocytes. Utilizing this pupal system, the heat-responsive period for increasing crossing-over in the Drosophila genome has been defined for the Χ chromosome and a portion of chromosome 2. The response is initiated close to the time of oocyte formation (premeiotic interphase) and is terminated after ~36 hr. During the 36-hr period different regions show characteristic responses, which vary in degree, in duration, and in initiation and termination points, so as to generate the beginning of a thermal recombination map for the Drosophila genome. Centromere regions exhibit the greatest increases in crossing-over for their respective chromosomes but are distinctly asynchronous in time; interstitial regions respond the least. Correlated autoradiographic studies have localized DNA replication in the oocyte to a ~24-hr period, which also begins close to oocyte formation (premeiotic interphase); late labeling in restricted regions, undetectable with the present method, could extend the period, as could prolonged synthesis in the oocyte. The results demonstrate that DNA replication and the heat-sensitive period for enhancement of crossing-over are coincident processes over most and possibly all of their length.

scholarly journals Genes Containing Long Introns Occupy Series of Bands and Interbands in Drosophila melanogaster Polytene Chromosomes

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 417
Author(s):  
Varvara A. Khoroshko ◽  
Galina V. Pokholkova ◽  
Victor G. Levitsky ◽  
Tatyana Yu. Zykova ◽  
Oksana V. Antonenko ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Polytene Chromosomes ◽  
Housekeeping Genes ◽  
Wide Distribution ◽  
Gene Location ◽  
Gene Arrangement ◽  
Drosophila Genome ◽  
Genetic Organization ◽  
Genome Wide ◽  
Bioinformatic Approaches

The Drosophila melanogaster polytene chromosomes are the best model for studying the genome organization during interphase. Despite of the long-term studies available on genetic organization of polytene chromosome bands and interbands, little is known regarding long gene location on chromosomes. To analyze it, we used bioinformatic approaches and characterized genome-wide distribution of introns in gene bodies and in different chromatin states, and using fluorescent in situ hybridization we juxtaposed them with the chromosome structures. Short introns up to 2 kb in length are located in the bodies of housekeeping genes (grey bands or lazurite chromatin). In the group of 70 longest genes in the Drosophila genome, 95% of total gene length accrues to introns. The mapping of the 15 long genes showed that they could occupy extended sections of polytene chromosomes containing band and interband series, with promoters located in the interband fragments (aquamarine chromatin). Introns (malachite and ruby chromatin) in polytene chromosomes form independent bands, which can contain either both introns and exons or intron material only. Thus, a novel type of the gene arrangement in polytene chromosomes was discovered; peculiarities of such genetic organization are discussed.

scholarly journals THE EFFECT OF RECOMBINATION-DEFECTIVE MEIOTIC MUTANTS ON FOURTH-CHROMOSOME CROSSING OVER IN DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 90 (4) ◽  
pp. 699-712
Author(s):  
L Sandler ◽  
Paul Szauter
Keyword(s):  
Drosophila Melanogaster ◽  
Spatial Distribution ◽  
The Other ◽  
Crossing Over ◽  
Chromosome 4 ◽  
Wild Type ◽  
Fourth Chromosome ◽  
Meiotic Mutants ◽  
Other Hand

ABSTRACT Crossing over was measured on the normally achiasmate fourth chromosome in females homozygous for one of our different recombination-defective meiotic mutants. Under the influence of those meiotic mutants that affect the major chromosomes by altering the spatial distribution of exchanges, meiotic fourth-chromosome recombinants were recovered irrespective of whether or not the meiotic mutant decreases crossing over on the other chromosomes. No crossing over, on the other hand, was detected on chromosome 4 in either wild type or in the presence of a meiotic mutant that decreases the frequency, but that does not affect the spatial distribution, of exchange on the major chromosomes. It is concluded from these observations that (a) in wild type there are regional constraints on exchange that can be attenuated or eliminated by the defects caused by recombination-defective meiotic mutants; (b) these very constraints account for the absence of recombination on chromosome 4 in wild type; and (c) despite being normally achiasmate, chromosome 4 responds to recombination-defective meiotic mutants in the same way as do the other chromosomes.

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