Gene Modifier
Mostrando 13-24 de 177 artigos, teses e dissertações.
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13. Selection, Generalized Transmission and the Evolution of Modifier Genes. I. the Reduction Principle
Modifier gene models are used to explore the evolution of features of organisms, such as the genetic system, that are not directly involved in the determination of fitness. Recent work has shown that a general "reduction principle" holds in models of selectively neutral modifiers of recombination, mutation, and migration. Here we present a framework for mode
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14. Genetic Interactions of Modifier Genes and Modifiable Alleles in Drosophila Melanogaster
We have examined the effects of mutations in the six allele-specific modifier genes su(Hw), e(w(e)), su(f), su(s), su(w(a)), and su(pr) on the expression of 18 modifiable alleles, situated at 11 loci. Ten of the modifiable alleles are associated with insertions of the gypsy retrotransposon and the others include alleles associated with insertions of copia an
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15. The Genetic Control and Biochemical Modification of Catechol Oxidase in Maize
Three isozyme variants of catechol oxidase have been shown to be determined by alleles of a gene, Cx, which has been located on chromosome 10 less than 0.1 recombination units from the endosperm marker du1.—The extractable form of the enzyme is modified by an endogeneous "modifier" which appears to function as an enzyme substrate. Enzyme and modifier are f
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16. The Evolutionary Development of Modifier Genes
The main findings of a study of the evolution of modifier gene frequencies in models of deterministic population genetics are presented. A wide variety of random mating systems are subject to selection with modifiers operating, in different cases, on mutation rates, dominance, migration between subpopulations, and linkage between other loci. In all these ins
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17. opaque-15, a maize mutation with properties of a defective opaque-2 modifier.
An opaque mutation was identified that reduces gamma-zein synthesis in maize endosperm. The mutation, opaque-15, causes a 2- to 3-fold reduction in gamma-zein mRNA and protein synthesis and reduces the proportion of the 27-kDa gamma-zein A gene transcript. Although the protein bodies in opaque-15 are similar in size and morphology compared to wild type, ther
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18. Diazinon Resistance, Fluctuating Asymmetry and Fitness in the Australian Sheep Blowfly, Lucilia Cuprina
Genetic evidence suggests that the evolution of resistance to the insecticide diazinon in Lucilia cuprina initially produced an increase in asymmetry. At that time resistant flies were presumed to be at a selective disadvantage in the absence of diazinon. Subsequent evolution in natural populations selected modifiers to ameliorate these effects. The fitness
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19. A Sex-Influenced Modifier in Drosophila That Affects a Broad Spectrum of Target Loci Including the Histone Repeats
A second chromosomal trans-acting modifier, Lightener of white (Low), modulates the phenotypic expression of various alleles of the white eye color gene. This modifier has an unusually broad spectrum of affected genes including white, brown, scarlet and the eye developmental genes, Bar and Lobe. In addition, Low weakly suppresses position effect variegation.
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20. Genetic Modifiers of the Phenotypic Level of Deoxyribonucleic Acid-Conferred Novobiocin Resistance in Haemophilus
Leidy, Grace (Columbia University, New York, N.Y.), Iris Jaffee, and Hattie E. Alexander. Genetic modifiers of the phenotypic level of deoxyribonucleic acid-conferred novobiocin resistance in Haemophilus. J. Bacteriol. 92:1464–1468. 1966.—An apparent increase in novobiocin resistance in Haemophilus aegyptius after a second exposure to a particular H. inf
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21. Early Onset of Severe Familial Amyotrophic Lateral Sclerosis with a SOD-1 Mutation: Potential Impact of CNTF as a Candidate Modifier Gene
Mutations in the copper/zinc superoxide dismutase 1 (SOD-1) gene are found in ∼20% of patients with familial amyotrophic lateral sclerosis (FALS), or amyotrophic lateral sclerosis 1. Here we describe a 25-year-old male patient who died from FALS after a rapid disease course of 11 mo. Sequencing of the SOD-1 gene revealed a heterozygous T→G exchange at po
The American Society of Human Genetics.
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22. Identification of the Modifier of Min 2 (Mom2) Locus, a New Mutation That Influences Apc-Induced Intestinal Neoplasia
Min (Multiple intestinal neoplasia) mice carry a dominant mutation in the adenomatous polyposis coli (Apc) gene and develop multiple adenomas throughout their intestinal tract (Moser et al. 1990; Su et al. 1992). Polyp multiplicity in Min mice is greatly influenced by genetic background. A modifier locus, Mom1 (Modifier of Min 1), was identified and localize
Cold Spring Harbor Laboratory Press.
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23. Differential inhibition of the Fas- and granule-mediated cytolysis pathways by the orthopoxvirus cytokine response modifier A/SPI-2 and SPI-1 protein.
Cytotoxic T lymphocytes are important effectors of antiviral immunity, and they induce target cell death either by secretion of cytoplasmic granules containing perforin and granzymes or by signaling through the Fas cell surface antigen. Although it is not known whether the granule-mediated and Fas-mediated cytolytic mechanisms share common components, protei
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24. The Sugary Gene in Maize as a Modifier of the Waxy Ratio