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Animal Biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
Drosophila melanogaster, also known as the fruit fly or vinegar fly, is one of the most studied organisms in biological research, particularly in genetics and developmental biology (Figure 7.5). This is because it is small and easy to grow in the laboratory, and its morphology is easy to identify once they are anesthetized, usually with ether, carbon dioxide gas, or by cooling them. It has a short lifespan of about 10 days at room temperature, so several generations can be studied within a few weeks. It has a high fecundity as females can lay >800 eggs in a lifetime. Males and females are readily distinguished and virgin females are easily isolated, facilitating genetic crossing. The mature larvae show giant chromosomes in the salivary glands called polytene chromosomes. It has only four pairs of chromosomes: three autosomes and one sex chromosome. Males do not show meiotic recombination, facilitating genetic studies. Recessive lethal “balancer chromosomes” carrying visible genetic markers can be used to keep stocks of lethal alleles in a heterozygous state without recombination because of multiple inversions in the balancer. Genetic transformation techniques have been available since 1987. Drosophila genes are traditionally named after the phenotype they cause when mutated. For example, the absence of a particular gene in Drosophila will result in a mutant embryo that does not develop a heart. Scientists have thus called this gene tinman, named after the Oz character of the same name.
Animal biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
D. melanogaster, also known as fruit fly or vinegar fly, is one of the most studied organisms in biological research, particularly in genetics and developmental biology (Figure 7.5). This is so because it is small and easy to grow in the laboratory, and their morphology is easy to identify once they are anesthetized usually with ether, carbon dioxide gas, or by cooling them. It has a short life span of about 10 days at room temperature, so several generations can be studied within a few weeks. It has a high fecundity; females can lay more than 800 eggs in a lifetime. Males and females are readily distinguished and virgin females are easily isolated, facilitating genetic crossing. The mature larvae show giant chromosomes in the salivary glands called polytene chromosomes. It has only four pairs of chromosomes: three autosomes and one sex chromosome. Males do not show meiotic recombination, facilitating genetic studies. Recessive lethal “balancer chromosomes” carrying visible genetic markers can be used to keep stocks of lethal alleles in a heterozygous state without recombination due to multiple inversions in the balancer. Genetic transformation techniques have been available since 1987. Drosophila genes are traditionally named after the phenotype they cause when mutated. For example, the absence of a particular gene in Drosophila will result in a mutant embryo that does not develop a heart. Scientists have thus called this gene tinman, named after the Oz character of the same name.
In vivo effects of 1,4-dioxane on genotoxic parameters and behavioral alterations in Drosophila melanogaster
Published in Journal of Toxicology and Environmental Health, Part A, 2022
SMART is based upon the genetic damage formation of dividing wing imaginal disc cells. This damage results in loss of heterozygosity (LOH) in larval development processes and is readily detectable in adult fly wings as mutant wing spots under the light microscope (Graf et al. 1984). The spots may occur via mutation (point mutation or deletion) or somatic recombination and normal and serrate wing (wings obtained from transheterozygous larvae and balancer heterozygous larvae). Analyses yield the opportunity to obtain quantitative determination of the recombinogenic activity of genotoxic compounds (Graf et al. 1998). Table 1 presents results detected in trans-heterozygous larvae and balancer heterozygous larvae exposed to different concentration of DXN. Exposure to DXN demonstrated that number of trans-heterozygous wings (mwh/flr3) were significantly increased for small single, large single, total mwh and total spot types at all concentrations. Examination of balancer-heterozygous wings (mwh/TM3) found that DXN at 0.1, 0.25, or 0.5 did not markedly affect number of small single spots, total mwh spots, and total spots. Recombination is suppressed by the effect of balancer chromosome in the balancer-heterozygous wings (serrated wings) and spots solely occur by mutation in this wings. Clone formation frequency results following DXN exposure of D. melanogaster are shown in Figure 8a. Data demonstrated that 0.1, 0.25, or 0.5% concentrations of DXN exerted genotoxic effects predominantly with somatic recombination.