Drosophilia virilise was completed with aceto orcein

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Drosophilia virilise was completed with aceto-orcein after a 10-minute incubation at room temperature (25°C). Magnification 400x. Are there some visible differences you can observe between your two temperature treatments? If yes, what are they? Should there be more puffs in the treatment at 37 °C compared to the one at 25 °C? Yes, there are visible differences between the polytene chromosomes at room temperature at 25°C and after being heat shocked at 37°C. Within the chromosome treated with heat shock the inter-bands are much larger, clearer, and a lighter colour. Some of the chromosomes in the sample also demonstrated signs of puffing, as a result of them being much larger, clearer, and lighter. The chromosomes at 25°C were smaller and less visible as they were physically darker, due to the lack of puffing keeping the parts of the polytene chromosome more condensed. Yes, you would expect more puffs from the treatment at 37°C as a result of the chromosomes puffing response to heat shocking. Are the polytene chromosomes physically interconnected? If yes, describe the structure you see. Yes, they are physically interconnected. The polytene chromosomes are interconnected in a scrambled ball shape within the nucleus. The scramble of the chromosomes creates a chromocenter from the centromeres.
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What is the ploidy of your polytene chromosomes? Justify your answer. The ploidy of the polytene chromosome is polyploidy. The ploidy is polyploidy due to the endoreplication of the chromosomes, the fly has a very high gene activity which allows the cells to have many copies of genes. In the figures above, the polytene
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  • Winter '09
  • MONTPETIT
  • DNA, polytene chromosomes, Drosophilia virilius

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