Analysis of Biological Development (K. Kalthoff)

Updates to Topic 24: Genetic and Molecular Analysis of Pattern Formation in Plants

Answers to Questions in the Text

Role of the constans+ Gene in Floral Induction (p. 651)

  1. In order to make their results conclusive, the investigators had to test whether dexamethasone was exerting its effects on plant flowering through the contans-glucocorticoid receptor fusion protein, as designed, or whether dexamethasone was acting independently in some unforeseen way. Which control experiment do you think the researchers should have done to settle this question? Answer: They provided dexamethasone to wild type – non-transformed – plants. The treatment had no effect, indicating that dexamethasone acted through the transgene product, that is, the contans-glucocorticoid receptor fusion protein.
  2. The results of this experiment do not show whether expression of the constans+ gene is controlled at the level of transcription. How could the authors have tested (and they did) whether this was the case? Answer: They observed that the concentration of constans mRNA increased significantly when plants were shifted from SD to LD conditions. They also knew that the flower-inducing effect of the constans+ gene under LD conditions depends on the number of wild-type alleles present and the strength of the promoters driving them.


To my green colleagues: Plant embryos are a stretch for me. If I am missing any important points let me know. (KK)

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