Author: Phillip Jennings ReitanPublisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 302
Book Description
A Study of the Developmental Effects of Some Embryonic Lethal Mutations in Drosophila Melanogaster
Author: Phillip Jennings ReitanPublisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 302
Book Description
A Comparison of the Developmental Effects of Two Lethal Mutations in Drosophila Melanogaster
Author: Katherine ArmstrongDevelopmental and Cytogenetic Studies on an Embryo Lethal Mutation in Drosophila Melanogaster
Author: Jyothi R. P.The Culture in Vitro of Cells from Lethal Embryos of Drosophila Melanogaster
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The merits of utilising the Drosophila melanogaster embryo for the genetic analysis of cellular differentiation are discussed. The advantages are seen to lie in the ease of isolation and manipulation of lethal mutations, and the possibility that mutants of specific developmental processes can be selected. A major disadvantage of the Drosophila embryo is considered to be the problem of discovering whether a lethal mutant directly affects a particular cell type or not; in the whole embryo, the specific effects of a lethal factor may often be confused with their developmental ramifications. It is proposed that in vitro culture might provide a straightforward method of assessing the effects of a lethal mutation on individual cell types.In vitro cultures were made from dispersed cells of gastrula-stage lethal embryos. In the early part of the work a number of temperature-sensitive embryonic lethals were isolated and one of them was cultured by a technique utilising bulk quantities of embryos. The major conclusion from this work was that especially careful attention would have to be paid to genetic background when culturing lethal mutants in vitro. Following this, a technique for the production of high quality cultures from single embryos was developed. Whereas a previously- reported technique had been claimed to give the differentiation of nerve and rnusclo cells, the new technique gavexiiithe differentiation of five identified larval cell types, and, furthermore, the cultueres could continue to develop for several weeks. This new technique of culturing sing le embryos was applied to a number of embryonic lethals, both unconditional and temperature-sensitive.The results of culturing experiments were consist ent with, and extended, those from earlier studies of the lethal mutants which had utilised other techniques (examination of live embryos and stained sections; in vivo culture). Whilst the results show that in vitro culture limits the possibility of deleterious interaction between different cell types, and therefore renders the identific ation of specific genetic effects more straightforward, they provide strong circumstantial evidence that some interactions do take place in vitro. The consequences of such interactions are discussed, and means for the assessment of their importance in the development of cultures of mutant cells are suggested. It is pointed out that it may be possible to use in vitro culture systems to experimentally analyse mutants of known cellular interactions.
Scientific Frontiers in Developmental Toxicology and Risk Assessment
Author: National Research CouncilPublisher: National Academies Press
ISBN: 0309070864
Category : Nature
Languages : en
Pages : 348
Book Description
Scientific Frontiers in Developmental Toxicology and Risk Assessment reviews advances made during the last 10-15 years in fields such as developmental biology, molecular biology, and genetics. It describes a novel approach for how these advances might be used in combination with existing methodologies to further the understanding of mechanisms of developmental toxicity, to improve the assessment of chemicals for their ability to cause developmental toxicity, and to improve risk assessment for developmental defects. For example, based on the recent advances, even the smallest, simplest laboratory animals such as the fruit fly, roundworm, and zebrafish might be able to serve as developmental toxicological models for human biological systems. Use of such organisms might allow for rapid and inexpensive testing of large numbers of chemicals for their potential to cause developmental toxicity; presently, there are little or no developmental toxicity data available for the majority of natural and manufactured chemicals in use. This new approach to developmental toxicology and risk assessment will require simultaneous research on several fronts by experts from multiple scientific disciplines, including developmental toxicologists, developmental biologists, geneticists, epidemiologists, and biostatisticians.
A Developmental Study of Lethal Factors in Drosophila Melanogaster
Author: Frank SetoEarly Embryonic Development of Animals
Author: Wolfgang HennigPublisher: Springer Science & Business Media
ISBN: 354047191X
Category : Science
Languages : en
Pages : 245
Book Description
Four of the major animal systems studied for the mechanisms of their early embryonic development are treated in this volume. The articles address the specific questions studied in the various systems, discuss the fundamental questions raised by the particular organism and explain the techniques used to find answers to these questions. Questions of patternformation, early organogenesis and the genetics of the early development arecovered as well as the question of parental imprinting phenomena in mammals which are important for the early differentiation. The development of the mouse, Drosophila, Caenorhabditis and the zebrafish is emphasized by leading experts of their fields, and current problems in each system are exposed. For the zebrafish the advantages of this new system for developmental biology studies are summarized and discussed in their values, while in the other system the emphasis is laid on one of the actual field of research.
Genetic and Developmental Properties of Sex-linked Recessive Temperature-sensitive Lethal Mutations Induced in Drosophila Melanogaster by Ethyl Methanesulfonate
Author: Barbara Karen DunnPublisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 478
Book Description
Developmental Genetics of the Mutation Female-lethal in Drosophila Melanogaster
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis presents an investigation into the developmental genetics of themutation Female-lethal of Drosophila melanogaster. The three knowneffects of mutation at the locus* recessive lethality of, dominantlethality of and sterility of females homozygous for the allele Female- slethal-sterile; were studied. It was considered that an investigation of the regulative mechanisms controlling sexual development would not only provide information about sexual differentiation, but also give an insight into the mechanisms controlling gene activity during development in general.Various genetic techniques were employed in the investigation of mutations at the locus. Complementation studies on alleles indicated that maybe a complex locus and that homozygosity for produces sterile femaleswhich do not possess ovaries. An investigation of the lethal phase of andindicated that is lethal during embryogenesis before and,therefore, that the mutation is a less severe change than Fl. Maleviability studies showed that is sex-specific, expressed only in females,and that male viability was not due to suppression by the Y-chromosome.The genetic backgrounds in which exerts dominant lethal expression couldsupport a role of in the regulation of rDNA, but other explanations arepossible. However, these studies proved that the dominant expression of is dependent upon maternal genotype. Alterations of phenotypic sex indicatedthat either acts prior to the sex-transforming mutants used, or is notrequired in any process which is ultimately expressed in terms of phenotypicsex. It was shown by dosage manipulation studies that the sex-limited lethalphenotype of was not due to the presence of two copies of Fl in females,indicating that is an amorph or hypomorph and that is a hypomorph.A clonal analysis of indicated that while tissue was lethal in gynandromorphs, in induced mosaics, clones were not lethal after 12 - 8 hours post-fertilization. These results would indicate that is not required in a cell-specific process due to the XX karyotype. No interaction of male and female tissue in the expression of FI was observed in gynandromorphs.It is concluded that codes for a product specifically required infemales prior to germ band shortening. The mutation is either an amorph or hypomorph while FI is a hypomorph. It is considered that is required for some process that is not related to the imaginal sex of the adult fly.
Author: Sheila J. Counce