scholarly journals A CASE OF HIGH RATE OF SPONTANEOUS MUTATION AFFECTING VIABILITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1973 ◽  
Vol 75 (1) ◽  
pp. 133-153
Author(s):  
Margaret Gale Kidwell ◽  
J F Kidwell ◽  
M Nei
Keyword(s):  
Mutation Rate ◽  
Spontaneous Mutation ◽  
High Rate ◽  
Mutation Rates ◽  
Genetic Constitution ◽  
Isogenic Line ◽  
Frequency Distributions ◽  
The Third ◽  
Lethal Mutations ◽  
Very High

ABSTRACT A spontaneous lethal mutation rate approximately twenty to thirty times greater than normal has been discovered in second and third chromosomes derived from an irradiated isogenic line and paired with marked inversion chromosomes. Mutations resulting in reductions of viability of varying magnitude short of complete lethality apparently also occur at a very high rate in the third but not in the second chromosome. The pattern of accumulation of lethal mutations over several generations and viability frequency distributions within generations have been studied in a number of independent experiments. High mutation rate occurs in heterozygous isogenic-derived second and third chromosomes, either together or apart, irrespective of the genetic constitution of nonhomologous chromosomes. High mutation rates were not observed using the same methods with chromosomes of an inbred line from a different source. The possible mechanisms responsible for these results are discussed.

MUTATION RATES FOR ENZYME AND MORPHOLOGICAL LOCI IN BARLEY (HORDEUM VULGARE L.)

Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 729-734
Author(s):  
A L Kahler ◽  
R W Allard ◽  
R D Miller
Keyword(s):  
Mutation Rate ◽  
Spontaneous Mutation ◽  
Mutation Rates ◽  
Isogenic Line ◽  
Probability Level ◽  
Short Term ◽  
Hordeum Vulgare L ◽  
Spontaneous Mutation Rate ◽  
Enzyme Loci ◽  
Morphological Variants

ABSTRACT Spontaneous mutation rates were estimated by assaying 84,126 seedlings of a highly homozygous barley line (isogenic line 2025) for five enzyme loci. No mutants were observed in 841,260 allele replications. This result excludes, at probability level 0.95, a spontaneous mutation rate larger than 3.56 x 10-6/locus/gamete/generation for these enzyme loci. Isogenic line 2025 also was scored for mutants at four loci governing morphological variants. No mutants were observed in 3,386,850 allele replications which indicates that the upper bound for the mutation rate for these loci is 8.85 x 10-7. It was concluded that, even though spontaneous mutation has been important in creating variability in the barley species at the loci scored, the rate is too low to have much affect on the short-term dynamics of barley populations.

scholarly journals Viral mutation rates: modelling the roles of within-host viral dynamics and the trade-off between replication fidelity and speed

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122047 ◽  
Author(s):  
Roland R. Regoes ◽  
Steven Hamblin ◽  
Mark M. Tanaka
Keyword(s):  
Life History ◽  
Mutation Rate ◽  
High Rate ◽  
Mutation Rates ◽  
Viral Dynamics ◽  
Trade Off ◽  
Trade Offs ◽  
Very High ◽  
Host Death

Many viruses, particularly RNA viruses, mutate at a very high rate per genome per replication. One possible explanation is that high mutation rates are selected to meet the challenge of fluctuating environments, including the host immune response. Alternatively, recent studies argue that viruses evolve under a trade-off between replication speed and fidelity such that fast replication is selected, and, along with it, high mutation rates. Here, in addition to these factors, we consider the role of viral life-history properties: namely, the within-host dynamics of viruses resulting from their interaction with the host. We develop mathematical models incorporating factors occurring within and between hosts, including deleterious and advantageous mutations, host death owing to virulence and clearance of viruses by the host. Beneficial mutations confer both a within-host and a transmission advantage. First, we find that advantageous mutations have only a weak effect on the optimal genomic mutation rate. Second, viral life-history properties have a large effect on the mutation rate. Third, when the speed–fidelity trade-off is included, there can be two locally optimal mutation rates. Our analysis provides a way to consider how life-history properties combine with biochemical trade-offs to shape mutation rates.

Scope of action of the immunoglobulin mutator system

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 118-121 ◽  
Author(s):  
Matthias R. Wabl ◽  
Hans-Martin Jäck ◽  
R. C. von Borstel ◽  
Charles M. Steinberg
Keyword(s):  
B Cell ◽  
Mutation Rate ◽  
Heavy Chain ◽  
B Lymphocyte ◽  
Somatic Hypermutation ◽  
Spontaneous Mutation ◽  
Cell Lineage ◽  
Variable Region ◽  
High Rate ◽  
Spontaneous Mutation Rate

The authors have developed a method to measure the rate of spontaneous mutations taking place in IgH, the gene encoding the immunoglobulin heavy chain. When an amber chain-termination codon mutates to a sense codon, translation of the polypeptide chain will be completed, and mutant cells producing the heavy chain can be detected with a fluorescent labelled antibody. The protocol used is the compartmentalization test which minimizes any effect of selection. In subclones of the pre-B lymphocyte line 18–81, the spontaneous mutation rate in the part of IgH encoding the variable region is somewhat greater than 10−5 mutations per base pair per generation. This supports the hypothesis that hypermutation is not dependent on cell stimulation by an antigen. In a hybrid between a cell of this line and a myeloma (which represents the terminal stage of the B-cell lineage), the mutation rate was too low to be determined by this test, less than 10−9. When the same loss to gain procedure system was used with an opal chain-terminating codon in the part of IgH encoding the constant region (Cμ), a high rate of reversion by deletion was found. Long (more than one exon) and short (less than one exon) deletions occurred at rates of 1.7 × 10−5 and 1.4 × 10−7 per generation, respectively. It is thought that the high rate of deletion is not related to somatic hypermutation but rather to DNA rearrangement during the heavy-chain class switch, which is occurring in these pre-B cell lines. The point mutation rate was too low to be detected above the background of deletion mutants, less than 5 × 10−8. The immunoglobulin mutator system works weakly, if at all, on two other, nonimmunoglobulin, genes tested: B2m (β2 microglobulin) and the gene for ouabain resistance.Key words: pre-B lymphocyte, B lymphocyte, spontaneous mutation rate, compartmentalization test, deletion mutation, hypermutation.

scholarly journals First Estimation of the Spontaneous Mutation Rate in Diatoms

2019 ◽  
Vol 11 (7) ◽  
pp. 1829-1837 ◽  
Author(s):  
Marc Krasovec ◽  
Sophie Sanchez-Brosseau ◽  
Gwenael Piganeau
Keyword(s):  
Mutation Rate ◽  
Spontaneous Mutation ◽  
Mutation Accumulation ◽  
Mutation Rates ◽  
Model Organisms ◽  
Base Substitution ◽  
Unicellular Eukaryote ◽  
Fundamental Parameter ◽  
Secondary Endosymbiosis ◽  
Spontaneous Mutation Rate

Abstract Mutations are the origin of genetic diversity, and the mutation rate is a fundamental parameter to understand all aspects of molecular evolution. The combination of mutation–accumulation experiments and high-throughput sequencing enabled the estimation of mutation rates in most model organisms, but several major eukaryotic lineages remain unexplored. Here, we report the first estimation of the spontaneous mutation rate in a model unicellular eukaryote from the Stramenopile kingdom, the diatom Phaeodactylum tricornutum (strain RCC2967). We sequenced 36 mutation accumulation lines for an average of 181 generations per line and identified 156 de novo mutations. The base substitution mutation rate per site per generation is μbs = 4.77 × 10−10 and the insertion–deletion mutation rate is μid = 1.58 × 10−11. The mutation rate varies as a function of the nucleotide context and is biased toward an excess of mutations from GC to AT, consistent with previous observations in other species. Interestingly, the mutation rates between the genomes of organelles and the nucleus differ, with a significantly higher mutation rate in the mitochondria. This confirms previous claims based on indirect estimations of the mutation rate in mitochondria of photosynthetic eukaryotes that acquired their plastid through a secondary endosymbiosis. This novel estimate enables us to infer the effective population size of P. tricornutum to be Ne∼8.72 × 106.

scholarly journals HIGH MUTABILITY IN MALE HYBRIDS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1980 ◽  
Vol 96 (2) ◽  
pp. 479-490 ◽  
Author(s):  
Michael J Simmons ◽  
Nancy A Johnson ◽  
Thomas M Fahey ◽  
Sue M Nellett ◽  
John D Raymond
Keyword(s):  
Drosophila Melanogaster ◽  
Mutation Rate ◽  
Reciprocal Cross ◽  
Mutation Rates ◽  
Mutation Induction ◽  
Hybrid Male ◽  
Lethal Mutations ◽  
The Cross ◽  
The Relationship ◽  
Reciprocal Mating

ABSTRACT The frequencies of sex-linked lethal mutations arising in hybrid male offspring from various crosses and in nonhybrid controls were determined. The hybrids were produced by crossing representative strains of the P-M system of hybrid dysgenesis in all possible combinations. Males from the cross of P males × M females had a mutation rate about 15 times higher than that of nonhybrid males from the P strain. Genetically identical males from the reciprocal cross had a mutation rate 3 to 4 times that of the nonhybrids. For crosses involving a Q strain, a significant increase in the mutation rate was detected in males produced by matings of Q males with M females. No increase was observed in genetically identical males from the reciprocal mating. Crosses between P and Q strains gave male hybrids with mutation rates not different from those of nonhybrids. Many of the lethals that occurred in hybrids from the cross of P males × M females appeared to be unstable; fewer lethals that arose in hybrids from the cross of Q males × M females were unstable. The relationship between P and Q strains is discussed with respect to a model of mutation induction in dysgenic hybrids.

scholarly journals Spontaneous mutation rate estimates for the principal malaria vectors Anopheles coluzzii and Anopheles stephensi

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Iliyas Rashid ◽  
Melina Campos ◽  
Travis Collier ◽  
Marc Crepeau ◽  
Allison Weakley ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Mutation Rate ◽  
Anopheles Stephensi ◽  
Spontaneous Mutation ◽  
False Negative ◽  
False Negative Rate ◽  
Mutation Rates ◽  
Malaria Vectors ◽  
Base Substitution ◽  
Anopheles Coluzzii

AbstractUsing high-depth whole genome sequencing of F0 mating pairs and multiple individual F1 offspring, we estimated the nuclear mutation rate per generation in the malaria vectors Anopheles coluzzii and Anopheles stephensi by detecting de novo genetic mutations. A purpose-built computer program was employed to filter actual mutations from a deep background of superficially similar artifacts resulting from read misalignment. Performance of filtering parameters was determined using software-simulated mutations, and the resulting estimate of false negative rate was used to correct final mutation rate estimates. Spontaneous mutation rates by base substitution were estimated at 1.00 × 10−9 (95% confidence interval, 2.06 × 10−10—2.91 × 10−9) and 1.36 × 10−9 (95% confidence interval, 4.42 × 10−10—3.18 × 10−9) per site per generation in A. coluzzii and A. stephensi respectively. Although similar studies have been performed on other insect species including dipterans, this is the first study to empirically measure mutation rates in the important genus Anopheles, and thus provides an estimate of µ that will be of utility for comparative evolutionary genomics, as well as for population genetic analysis of malaria vector mosquito species.

THE EFFECT OF AGING AND HEAT ON THE CHROMOSOMAL MUTATION RATES IN MAIZE AND BARLEY

1933 ◽  
Vol 9 (3) ◽  
pp. 261-264 ◽  
Author(s):  
F. H. Peto
Keyword(s):  
Mutation Rate ◽  
Secondary Constriction ◽  
Heat Treatments ◽  
Common Type ◽  
Mutation Rates ◽  
Chromosomal Mutation ◽  
Corn Plants ◽  
Mutant Cells ◽  
Very High

The recent discovery by Navashin (3), that the chromosomal mutation rate in Crepis was influenced by aging of the seed, has been corroborated by observations on the mutation rate of corn plants grown from seed of various ages.A very high chromosomal mutation rate in barley was induced by heat treatments of seed under various conditions of humidity. The most common type of aberration resulting from these treatments appeared to be fracture of the chromosomes either at the attachment constriction, the secondary constriction or the point of attachment of the trabants. The reattachment of fragments to other chromosomes was observed in two instances.Considerable importance is attached to the discovery that a large proportion of the mutant cells are eliminated during the growth of the plant. The principle that only the fittest survive seems equally true of cells as of individuals and groups of plants or animals.

scholarly journals Spontaneous Mutation Rate of Measles Virus: Direct Estimation Based on Mutations Conferring Monoclonal Antibody Resistance

1999 ◽  
Vol 73 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Stephanie J. Schrag ◽  
Paul A. Rota ◽  
William J. Bellini
Keyword(s):  
Monoclonal Antibody ◽  
Mutation Rate ◽  
Measles Virus ◽  
Spontaneous Mutation ◽  
Single Point ◽  
Test Method ◽  
Mutation Rates ◽  
Viral Population ◽  
Single Point Mutation ◽  
Direct Estimate

ABSTRACT High mutation rates typical of RNA viruses often generate a unique viral population structure consisting of a large number of genetic microvariants. In the case of viral pathogens, this can result in rapid evolution of antiviral resistance or vaccine-escape mutants. We determined a direct estimate of the mutation rate of measles virus, the next likely target for global elimination following poliovirus. In a laboratory tissue culture system, we used the fluctuation test method of estimating mutation rate, which involves screening a large number of independent populations initiated by a small number of viruses each for the presence or absence of a particular single point mutation. The mutation we focused on, which can be screened for phenotypically, confers resistance to a monoclonal antibody (MAb 80-III-B2). The entire H gene of a subset of mutants was sequenced to verify that the resistance phenotype was associated with single point mutations. The epitope conferring MAb resistance was further characterized by Western blot analysis. Based on this approach, measles virus was estimated to have a mutation rate of 9 × 10−5 per base per replication and a genomic mutation rate of 1.43 per replication. The mutation rates we estimated for measles virus are comparable to recent in vitro estimates for both poliovirus and vesicular stomatitis virus. In the field, however, measles virus shows marked genetic stability. We briefly discuss the evolutionary implications of these results.

scholarly journals The Rate and Character of Spontaneous Mutation in an RNA Virus

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1505-1511 ◽  
Author(s):  
José M Malpica ◽  
Aurora Fraile ◽  
Ignacio Moreno ◽  
Clara I Obies ◽  
John W Drake ◽  
...  
Keyword(s):  
Mutation Rate ◽  
Movement Protein ◽  
Rna Viruses ◽  
Rna Virus ◽  
Spontaneous Mutation ◽  
Mutation Rates ◽  
Lower Side ◽  
Mutation Process ◽  
Spontaneous Mutation Rate ◽  
Mutant Frequency

Abstract Estimates of spontaneous mutation rates for RNA viruses are few and uncertain, most notably due to their dependence on tiny mutation reporter sequences that may not well represent the whole genome. We report here an estimate of the spontaneous mutation rate of tobacco mosaic virus using an 804-base cognate mutational target, the viral MP gene that encodes the movement protein (MP). Selection against newly arising mutants was countered by providing MP function from a transgene. The estimated genomic mutation rate was on the lower side of the range previously estimated for lytic animal riboviruses. We also present the first unbiased riboviral mutational spectrum. The proportion of base substitutions is the same as that in a retrovirus but is lower than that in most DNA-based organisms. Although the MP mutant frequency was 0.02-0.05, 35% of the sequenced mutants contained two or more mutations. Therefore, the mutation process in populations of TMV and perhaps of riboviruses generally differs profoundly from that in populations of DNA-based microbes and may be strongly influenced by a subpopulation of mutator polymerases.

scholarly journals MUTATOR ACTIVITY OF PETITE STRAINS OF SACCHAROMYCES CEREVISIAE

Genetics ◽  
1976 ◽  
Vol 83 (4) ◽  
pp. 645-653
Author(s):  
Fred Flury ◽  
R C von Borstel ◽  
D H Williamson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Mutation Rate ◽  
Frameshift Mutation ◽  
Spontaneous Mutation ◽  
Nuclear Genes ◽  
Mutation Rates ◽  
Spontaneous Mutation Rate ◽  
Mutator Activity ◽  
Missense Allele

ABSTRACT Petite strains in Saccharomyces exhibit enhanced spontaneous mutation rates of nuclear genes regardless of whether they are cytoplasmically or nuclearly inherited, or whether or not the cytoplasmic petite strains have mitochondrial DNA. In petite strains, the mutation rate for the nonsense allele lys1-1 is enhanced by a factor of 3-6 and for the missense allele his1-7 by a factor of 2 as compared with their grande counterparts. The reversion of a third allele, the putative frameshift mutation, hom3-10, is not enhanced in a petite background. The results indicate that the spontaneous mutation rate of an organism can be altered by indirect intracellular influences.

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