scholarly journals Genetic decay of balancer chromosomes inDrosophila melanogaster

Fly ◽  
2013 ◽  
Vol 7 (3) ◽  
pp. 184-186 ◽  
Author(s):  
Quenta Araye ◽  
Kyoichi Sawamura
Keyword(s):  
Balancer Chromosomes

scholarly journals Nature of Deleterious Mutation Load in Drosophila

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1993-1999 ◽  
Author(s):  
Peter D Keightley
Keyword(s):  
Deleterious Mutation ◽  
Spontaneous Mutation ◽  
Mutation Accumulation ◽  
Mutation Rates ◽  
Mutation Load ◽  
Spontaneous Mutation Rate ◽  
A Minor ◽  
Chromosome I ◽  
Balancer Chromosomes ◽  
Balancer Chromosome

Much population genetics and evolution theory depends on knowledge of genomic mutation rates and distributions of mutation effects for fitness, but most information comes from a few mutation accumulation experiments in Drosophila in which replicated chromosomes are sheltered from natural selection by a balancer chromosome. I show here that data from these experiments imply the existence of a large class of minor viability mutations with approximately equivalent effects. However, analysis of the distribution of viabilities of chromosomes exposed to EMS mutagenesis reveals a qualitatively different distribution of effects lacking such a minor effects class. A possible explanation for this difference is that transposable element insertions, a common class of spontaneous mutation event in Drosophila, frequently generate minor viability effects. This explanation would imply that current estimates of deleterious mutation rates are not generally applicable in evolutionary models, as transposition rates vary widely. Alternatively, much of the apparent decline in viability under spontaneous mutation accumulation could have been nonmutational, perhaps due to selective improvement of balancer chromosomes. This explanation accords well with the data and implies a spontaneous mutation rate for viability two orders of magnitude lower than previously assumed, with most mutation load attributable to major effects.

scholarly journals Does RNA interference influence meiotic crossing over in Drosophila melanogaster?

2008 ◽  
Vol 90 (3) ◽  
pp. 253-258 ◽  
Author(s):  
ERIC W. CROSS ◽  
MICHAEL J. SIMMONS
Keyword(s):  
Drosophila Melanogaster ◽  
Rna Interference ◽  
X Chromosome ◽  
Maternal Effect ◽  
Crossing Over ◽  
Crossover Frequency ◽  
Chromosome Iii ◽  
Chromosome Ii ◽  
Balancer Chromosomes ◽  
Balancer Chromosome

SummaryMutations in the RNA interference (RNAi) genes aubergine (aub), homeless and piwi were tested for effects on the frequency, distribution and coincidence of meiotic crossovers in the long arm of the X chromosome. Some increases in crossover frequency were seen in these tests, but they may have been due to a maternal effect of the balancer chromosomes that were used to maintain the RNAi mutations in stocks rather than to the RNAi mutations themselves. These same balancers produced strong zygotic interchromosomal effects when tested separately. Mutations in aub and piwi did not affect the frequency of crossing over in the centric heterochromatin of chromosome II; nor did a balancer chromosome III.

Natural selection with nuclear and cytoplasmic transmission. III. Joint analysis of segregation and mtDNA in Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 118 (3) ◽  
pp. 471-481
Author(s):  
A G Clark ◽  
E M Lyckegaard
Keyword(s):  
Statistical Tests ◽  
Statistical Significance ◽  
Geographic Origin ◽  
Joint Analysis ◽  
Central Pennsylvania ◽  
Mtdna Sequence ◽  
Site Variation ◽  
Linear Contrasts ◽  
Balancer Chromosomes ◽  
Cytoplasmic Variation

Abstract Despite the widespread use of mitochondrial DNA by evolutionary geneticists, relatively little effort has been spent assessing the magnitude of forces maintaining mtDNA sequence diversity. In this study the influence of cytoplasmic variation on viability in Drosophila was examined by analysis of second chromosome segregation. A factorial experiment with balancer chromosomes permitted the effects of cytoplasma and reciprocal crosses to be individually distinguished. The first test used six lines of diverse geographic origin, testing the segregation of all six second chromosomes in all six cytoplasms. The second and third tests were also factorial designs, but used flies from one population in central Pennsylvania. The fourth test was a large chain cross, using 28 lines from the same Pennsylvania population. Only the first test detected a significant nuclear-cytoplasmic effect. Restriction site variation in the mtDNA of all of these lines was assayed by Southern blotting, and statistical tests were performed in an effort to detect an influence of mtDNA type on fitness components. Posterior linear contrasts revealed an effect of mtDNA on segregation only among lines of diverse geographic origin. Within a population, no such influence was detected, even though the experiment was sufficiently large to have revealed statistical significance of a 0.5% segregation difference with a 57% probability.

Constructing balancer chromosomes for genetic screens in Drosophila hydei

1992 ◽  
Vol 83-83 (6-7) ◽  
pp. 821-826 ◽  
Author(s):  
J. H. P. Hackstein ◽  
R. Hochstenbach ◽  
F. M. A. van Breugel
Keyword(s):  
Genetic Screens ◽  
Drosophila Hydei ◽  
Balancer Chromosomes

scholarly journals GFP-tagged balancer chromosomes for Drosophila melanogaster

2000 ◽  
Vol 91 (1-2) ◽  
pp. 451-454 ◽  
Author(s):  
David Casso ◽  
Felipe-Andrés Ramı́rez-Weber ◽  
Thomas B. Kornberg
Keyword(s):  
Drosophila Melanogaster ◽  
Balancer Chromosomes

scholarly journals Engineering new balancer chromosomes in C. elegans via CRISPR/Cas9

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Satoru Iwata ◽  
Sawako Yoshina ◽  
Yuji Suehiro ◽  
Sayaka Hori ◽  
Shohei Mitani
Keyword(s):  
C Elegans ◽  
Balancer Chromosomes

scholarly journals N-Ethyl-N-Nitrosourea Mutagenesis: Boarding the Mouse Mutant Express

2005 ◽  
Vol 69 (3) ◽  
pp. 426-439 ◽  
Author(s):  
Sabine P. Cordes
Keyword(s):  
Genetic Mapping ◽  
Large Scale ◽  
Random Mutagenesis ◽  
Small Scale ◽  
Mouse Mutant ◽  
Genetic Screens ◽  
Screen Design ◽  
Mouse Mutants ◽  
Balancer Chromosomes ◽  
Forward Mutagenesis

SUMMARY In the mouse, random mutagenesis with N-ethyl-N-nitrosourea (ENU) has been used since the 1970s in forward mutagenesis screens. However, only in the last decade has ENU mutagenesis been harnessed to generate a myriad of new mouse mutations in large-scale genetic screens and focused, smaller efforts. The development of additional genetic tools, such as balancer chromosomes, refinements in genetic mapping strategies, and evolution of specialized assays, has allowed these screens to achieve new levels of sophistication. The impressive productivity of these screens has led to a deluge of mouse mutants that wait to be harnessed. Here the basic large- and small-scale strategies are described, as are the basics of screen design. Finally, and importantly, this review describes the mechanisms by which such mutants may be accessed now and in the future. Thus, this review should serve both as an overview of the power of forward mutagenesis in the mouse and as a resource for those interested in developing their own screens, adding onto existing efforts, or obtaining specific mouse mutants that have already been generated.

scholarly journals GFP-tagged balancer chromosomes for Drosophila melanogaster

1999 ◽  
Vol 88 (2) ◽  
pp. 229-232 ◽  
Author(s):  
David Casso ◽  
Felipe-Andrés Ramı́rez-Weber ◽  
Thomas B Kornberg
Keyword(s):  
Drosophila Melanogaster ◽  
Balancer Chromosomes

scholarly journals Identification and Characterization of Breakpoints and Mutations on Drosophila melanogaster Balancer Chromosomes

2020 ◽  
Vol 10 (11) ◽  
pp. 4271-4285 ◽  
Author(s):  
Danny E. Miller ◽  
Lily Kahsai ◽  
Kasun Buddika ◽  
Michael J. Dixon ◽  
Bernard Y. Kim ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Repetitive Sequences ◽  
Intestinal Cell ◽  
Induced Mutations ◽  
Telomeric Sequences ◽  
Long Read ◽  
The Stability ◽  
Induced Apoptosis ◽  
Balancer Chromosomes

Balancers are rearranged chromosomes used in Drosophila melanogaster to maintain deleterious mutations in stable populations, preserve sets of linked genetic elements and construct complex experimental stocks. Here, we assess the phenotypes associated with breakpoint-induced mutations on commonly used third chromosome balancers and show remarkably few deleterious effects. We demonstrate that a breakpoint in p53 causes loss of radiation-induced apoptosis and a breakpoint in Fucosyltransferase A causes loss of fucosylation in nervous and intestinal tissue—the latter study providing new markers for intestinal cell identity and challenging previous conclusions about the regulation of fucosylation. We also describe thousands of potentially harmful mutations shared among X or third chromosome balancers, or unique to specific balancers, including an Ankyrin 2 mutation present on most TM3 balancers, and reiterate the risks of using balancers as experimental controls. We used long-read sequencing to confirm or refine the positions of two inversions with breakpoints lying in repetitive sequences and provide evidence that one of the inversions, In(2L)Cy, arose by ectopic recombination between foldback transposon insertions and the other, In(3R)C, cleanly separates subtelomeric and telomeric sequences and moves the subtelomeric sequences to an internal chromosome position. In addition, our characterization of In(3R)C shows that balancers may be polymorphic for terminal deletions. Finally, we present evidence that extremely distal mutations on balancers can add to the stability of stocks whose purpose is to maintain homologous chromosomes carrying mutations in distal genes. Overall, these studies add to our understanding of the structure, diversity and effectiveness of balancer chromosomes.

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