A computer program for the generation of problems in genetics for teaching purposes.
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Computer-Assisted Instruction↗
Biomedical subjects
J L Micol
Publications and source records attributed to J L Micol.
Genetic analysis of "transvection" effects involving contrabithorax mutations in Drosophila melanogaster.
Contrabithorax (Cbx) alleles are dominant mutations in the Ultrabithorax (Ubx) gene of Drosophila that cause its ectopic expression in the mesothorax. We have studied the role of the homologous chromosome in the mesothoracic phenotype in several Cbx heterozygotes. None of the Cbx alleles studied shows variations in phenotype with extra doses of the Ubx gene. Only Cbx2 and CbxIRM (a revertant of Cbx1) show synapsis-dependent gene expression ("transvection"). The mesothoracic phenotypes of CbxIRM and Cbx2 heterozygotes are strongly modified when the homologous chromosome carries breakpoints proximal to or at the Ubx locus or null alleles of this gene. These lesions in the homologous chromosome enhance the Cbx2 mutant phenotype and reduce that of CbxIRM one. The genetic analysis of these transvection effects suggests that the transcription of the CbxIRM and Cbx2 alleles depends on RNAs of short radius of action from the homologous Ubx gene.
Alleles↗
Two different approaches to computer-aided teaching of microbial genetics.
Two computer packages have been developed to teach bacterial genetics on an introductory genetics course for undergraduate students in biology. The first package, 'CONJUGACION', is designed to teach bacterial conjugation and its genetic outcomes. It includes four main parts. Firstly, a tutorial part presents a theoretical framework using screens of text and animated graphics. Secondly, an interactive concept application section requires students to carry out experiments for the determination of the correct sex and genotype of 10 bacterial strains. The third part uses the previously obtained data for simulating interrupted mating experiments and mapping the bacterial genome. Finally, an evaluation section allows the students to test their understanding through a series of multiple choice questions. The second package, 'LURIDEL', is intended for teaching the preadaptative character of mutation in bacterial populations on the basis of the fluctuation test of Luria and Delbrück. It simulates, graphically, the appearance of mutations in microbial cultures and gives results of simulated fluctuation experiments. Programs were written under the PCOS operating system in MBASIC extended to graphics for running on Olivetti M20 microcomputers.
Computer-Assisted Instruction↗
A method for the selection of mutants of Phycomyces blakesleeanus defective in germination.
A simple method for the physical separation of dormant and germinated cells of Phycomyces blakesleeanus has been designed. Separation was attained by isopycnic centrifugation in a preformed discontinuous density gradient of Urografin. In this gradient, dormant spores and active cells at two different stages of germination were separated in three homogeneous and clearly distinct bands. The method has been used to follow the kinetics of the variation of cellular density during germination of wild type spores and to select for mutants temperature-sensitive for heat-shock induced germination. Sixty-nine mutants have been isolated by various procedures which include a separation step in the described Urografin gradient.
Centrifugation, Density Gradient↗
Characterization of Phycomyces blakesleeanus mutants temperature-sensitive for heat-shock induced germination.
Sixty-nine mutants of the fungus Phycomyces blakesleeanus, temperature-sensitive for heat-shock induced germination, have been characterized. All of them show a low viability at 26 degrees C and normal viability at 16 degrees C. Eleven mutants recover the wild type phenotype if yeast extract is added to the minimal medium; the mutant phenotype of eight of these mutants is also suppressed by the addition of putrescine or other polyamines. The majority of the mutants are affected very early in germination. Spontaneous, heat-shock and acetate induced germination are not equally impaired by some of the mutations, so specific and independent steps seem to be involved in part of the activation mechanism of germination.
Genes, Fungal↗