scholarly journals Construction of an Unstable Ring-X Chromosome Bearing the Autosomal Dopa Decarboxylase Gene in Drosophila melanogaster and Analysis of Ddc Mosaics

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 305-311
Author(s):  
Donald A Gailey ◽  
Deborah L Bordne ◽  
Ana Maria Vallés ◽  
Jeffrey C Hall ◽  
Kalpana White
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Recombination Event ◽  
P Element ◽  
Dopa Decarboxylase ◽  
Somatic Instability ◽  
Absolute Requirement ◽  
Double Recombination ◽  
Double Recombination Event

ABSTRACT An unstable Ring-X chromosome, Ddc  +- Ring-X carrying a cloned Dopa decarboxylase (Ddc) encoding segment was constructed. The construction involved a double recombination event between the unstable Ring-X, R(1)wvC and a Rod-X chromosome which contained a P-element mediated Ddc  + insert. The resulting Ddc  +-Ring-X chromosome behaves similarly to the parent chromosome with respect to somatic instability. The Ddc  +-Ring-X chromosome was used to generate Ddc mosaics. Analyses of Ddc mosaics revealed that while there was no absolute requirement for the Ddc  + expression in either the epidermis or the nervous system, very large mutant clones did affect the viability of the mosaic.

scholarly journals Norovirus recombination

2007 ◽  
Vol 88 (12) ◽  
pp. 3347-3359 ◽  
Author(s):  
Rowena A. Bull ◽  
Mark M. Tanaka ◽  
Peter A. White
Keyword(s):  
High Frequency ◽  
Driving Force ◽  
Recombination Event ◽  
Viral Evolution ◽  
Rna Recombination ◽  
Recombination Point ◽  
The Family ◽  
Double Recombination ◽  
Double Recombination Event ◽  
Recombination Breakpoints

RNA recombination is a significant driving force in viral evolution. Increased awareness of recombination within the genus Norovirus of the family Calicivirus has led to a rise in the identification of norovirus (NoV) recombinants and they are now reported at high frequency. Currently, there is no classification system for recombinant NoVs and a widely accepted recombinant genotyping system is still needed. Consequently, there is duplication in reporting of novel recombinants. This has led to difficulties in defining the number and types of recombinants in circulation. In this study, 120 NoV nucleotide sequences were compiled from the current GenBank database and published literature. NoV recombinants and their recombination breakpoints were identified using three methods: phylogenetic analysis, SimPlot analysis and the maximum χ 2 method. A total of 20 NoV recombinant types were identified in circulation worldwide. The recombination point is the ORF1/2 overlap in all isolates except one, which demonstrated a double recombination event within the polymerase region.

scholarly journals Genetic and molecular analysis of repression in the P–M system of hybrid dysgenesis in Drosophila melanogaster

1991 ◽  
Vol 57 (3) ◽  
pp. 213-226 ◽  
Author(s):  
Ellen M. Heath ◽  
Michael J. Simmons
Keyword(s):  
Drosophila Melanogaster ◽  
Maternal Effects ◽  
X Chromosome ◽  
Gonadal Dysgenesis ◽  
Inbred Lines ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
P Elements ◽  
Two Generations ◽  
Highly Correlated

SummaryTwelve inbred lines derived from an M′ strain of Drosophila melanogaster were used to study the repression of P-element-mediated hybrid dysgenesis. Initial assessments indicated that the lines differed in the ability to repress gonadal dysgenesis, and that this ability was highly correlated with the ability to repress snw hypermutability. Later assessments indicated that most of the lines with low or intermediate repression potential evolved to a state of higher repression potential; however, Southern analyses failed to reveal significant changes in the array of genomic P elements that could account for this evolution. In addition, none of the lines possessed the incomplete P element known as KP, which has been proposed to explain repression in some D. melanogaster strains. One of the lines maintained intermediate repression potential throughout the period of study (52 generations), indicating that the intermediate condition was not intrinsically unstable. Genetic analyses demonstrated that in some of the lines, repression potential was influenced by factors that were inherited maternally through at least two generations; however, these factors were not as influential as those in a classic P cytotype strain. Additional tests with a dysgenesis-inducing X chromosome called T-5 indicated that repression itself was mediated by a combination of maternal effects and paternally inherited factors that were expressed after fertilization. These tests also suggested that in some circumstances, the P transposase, or its message, might be transmitted through the maternal cytoplasm.

scholarly journals Repression of Hybrid Dysgenesis in Drosophila melanogaster by Combinations of Telomeric P-Element Reporters and Naturally Occurring P Elements

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1857-1866 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Laurent Marin ◽  
Monique Lehmann ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Chromatin Structure ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
Pericentromeric Heterochromatin ◽  
Combination Effect ◽  
P Elements ◽  
Naturally Occurring ◽  
Nuclear Location

Abstract In Drosophila melanogaster, hybrid dysgenesis occurs in the germline of flies produced by crosses between females lacking P elements and males carrying 25–55 P elements. We have previously shown that a complete maternally inherited repression of P transposition in the germline (P cytotype) can be elicited by only two autonomous P elements located at the X chromosome telomere (cytological site 1A). We have tested whether P transgenes at 1A, unable to code for a P-repressor, may contribute to the repression of P elements. Females carrying a P-lacZ transgene at 1A [“P-lacZ(1A)”], crossed with P males, do not repress dysgenic sterility in their progeny. However, these P-lacZ(1A) insertions, maternally or paternally inherited, contribute to P-element repression when they are combined with other regulatory P elements. This combination effect is not seen when the P-lacZ transgene is located in pericentromeric heterochromatin or in euchromatin; however a P-w,ry transgene located at the 3R chromosome telomere exhibits the combination effect. The combination effect with the P-lacZ(1A) transgene is impaired by a mutant Su(var)205 allele known to impair the repression ability of the autonomous P elements at 1A. We hypothesized that the combination effect is due to modification of the chromatin structure or nuclear location of genomic P elements.

scholarly journals Recombination analysis reveals a double recombination event in hepatitis E virus

2010 ◽  
Vol 7 (1) ◽  
pp. 129 ◽  
Author(s):  
Hua Wang ◽  
Wen Zhang ◽  
Bin Ni ◽  
Hongxing Shen ◽  
Yuyu Song ◽  
...  
Keyword(s):  
Recombination Event ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Recombination Analysis ◽  
Double Recombination ◽  
Double Recombination Event

scholarly journals The maternally inherited regulation of P elements in Drosophila melanogaster can be elicited by two P copies at cytological site 1A on the X chromosome.

Genetics ◽  
1991 ◽  
Vol 129 (2) ◽  
pp. 501-512 ◽  
Author(s):  
S Ronsseray ◽  
M Lehmann ◽  
D Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
P Element ◽  
P Elements ◽  
Element Activity ◽  
High Level ◽  
Regulatory Properties ◽  
Cellular Condition

Abstract Two P elements, inserted at the cytological site 1A on an X chromosome from an Drosophila melanogaster natural population (Lerik, USSR), were isolated by genetic methods to determine if they are sufficient to cause the P cytotype, the cellular condition that regulates the P family of transposable element. The resulting "Lerik P(1A)" line (abbreviated "Lk-P(1A)") carries only one P element in situ hybridization site but genomic Southern analysis indicates that this site contains two, probably full length, P copies separated by at least one EcoRI cleavage site. Because the Lk-P(1A) line shows some transposase activity, at least one of these two P elements is autonomous. The Lk-P(1A) line fully represses germline P element activity as judged by the GD sterility and snw hypermutability assays; this result shows that the P cytotype can be elicited by only two P element copies. However, the Lk-P(1A) line does not fully repress delta 2-3(99B) transposase activity in the soma, although it fully represses delta 2-3(99B) transposase activity in the germline (delta 2-3(99B) is an in vitro modified P element that produces a high level of transposase activity in both the germline and the soma). The germline regulatory properties of the Lk-P(1A) line are maternally transmitted, even when the delta 2-3(99B) element is used as the source of transposase. By contrast, the partial regulation of delta 2-3(99B) somatic activity is chromosomally inherited. These results suggest that the regulatory P elements of the Lk-P(1A) line are inserted near a germline-specific enhancer.

Further evidence reveals that okra mottle virus arose from a double recombination event

2012 ◽  
Vol 158 (1) ◽  
pp. 181-186 ◽  
Author(s):  
Leonardo C. Albuquerque ◽  
Silvia A. Aranha ◽  
Fernanda R. Fernandes ◽  
Alice K. Inoue-Nagata
Keyword(s):  
Recombination Event ◽  
Mottle Virus ◽  
Double Recombination ◽  
Double Recombination Event

The genetic and molecular organization of the Dopa decarboxylase gene cluster of Drosophila melanogaster.

Genetics ◽  
1995 ◽  
Vol 141 (2) ◽  
pp. 629-655 ◽  
Author(s):  
D G Stathakis ◽  
E S Pentz ◽  
M E Freeman ◽  
J Kullman ◽  
G R Hankins ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Cluster ◽  
Rflp Analysis ◽  
P Element ◽  
Molecular Organization ◽  
Gene Location ◽  
Dopa Decarboxylase ◽  
The One ◽  
Endonuclease Mapping ◽  
New Alleles

Abstract We report the complete molecular organization of the Dopa decarboxylase gene cluster. Mutagenesis screens recovered 77 new Df(2L)TW130 recessive lethal mutations. These new alleles combined with 263 previously isolated mutations in the cluster to define 18 essential genes. In addition, seven new deficiencies were isolated and characterized. Deficiency mapping, restriction fragment length polymorphism (RFLP) analysis and P-element-mediated germline transformation experiments determined the gene order for all 18 loci. Genomic and cDNA restriction endonuclease mapping, Northern blot analysis and DNA sequencing provided information on exact gene location, mRNA size and transcriptional direction for most of these loci. In addition, this analysis identified two transcription units that had not previously been identified by extensive mutagenesis screening. Most of the loci are contained within two dense subclusters. We discuss the effectiveness of mutagens and strategies used in our screens, the variable mutability of loci within the genome of Drosophila melanogaster, the cytological and molecular organization of the Ddc gene cluster, the validity of the one band-one gene hypothesis and a possible purpose for the clustering of genes in the Ddc region.

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