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shuimuzhao金虫 (初入文坛)
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那位遗传学大侠能帮我回答这个很有意思的问题
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You identify a mutant that is wildtype at 18C, but that dies as a result of a defect in heart development (thus the name of the mutant “broken heart”) when raised continuously at 25C. A. Describe a genetic approach for how you could distinguish between the following hypotheses: -- The temperature-sensitive phenotype is the null phenotype. It is simply a fact of the activity of this gene that it is not required at 18C. -- This is a temperature sensitive allele, which shows the loss-of-function phenotype only at 25C. B. Now lets suppose that you determine that the mutation is a ts allele. Genes are often expressed in broad patterns in time and space, even though they may only be needed for a process within a much narrower time window. Describe how you could use up-and down-shifts in temperature to identify the period during which broken heart acts to promote wildtype development. Draw a timeline of development and indicate when you are carrying out your shifts and in which directions to give yourself as much information about the requirement for broken heart function as possible. Assume that broken heart is required during initial heart specification in the embryo and at the transition between the larvae/pupae and the adult. |
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