1) State what is the generalbiological question that the authors are askingby analyzing the double mutantin the sunflower. Briefly explain its overall importanceto plant biology.
2) Briefly explain the evolutionary relationship between the two types of flower morphology described in the paper and how they affect pollination and plant diversification.
3) Briefly describe the two different types of florets found in awild type sunflower. Explain how florets morphology and distribution is different indouble and tubular mutants.
4) To generate F1 hybrid offspring, a wild-type plant was crossed with a "weak" semi-doublemutant (Primrose), which shows an intermediate phenotype. Explain why the authors did not usea plant with a full doublephenotypefor this cross.
5) Why the tubular phenotype is not observed in the F1 progeny?
6) The F2progenyfrom a semi-double F1 plantshows a 1:2:1 phenotypic ratio between wild-type: semi-double: double, confirming that the double allele is co-dominant to the wild-type allele. What phenotypicclasses and ratioswould you observe in the F2 if the double allele wascompletely dominant to the wild-type allele?Draw the crossusing the allele abbreviations used in the paper and show the expected phenotype/genotype correlations and ratios.
7) Briefly describe the DNA alterations found in the two different mutations, HaCYCc-dblandHaCYCc-tubthat causethe doubleand tubularphenotypes, respectively.
8) Briefly describe how the two mutations affect differently the expression of the HaCYCcgenein the double and tubular flowers.(Hint: look at figure 4, top graph to answer this question)
9) State whether double is a gain-of-functionor a loss of function mutation and explain your answer
10) How does the gain and loss of function nature of the double and tubular mutation correlatesto theirdominant orrecessive behavior
Challenge questions for "extra" extra 4 points.
The authors state that tubular and double arealleles of the same gene because no tubular-double flowers (flowers that show both phenotypes)are observed in the F2 progeny.
a. Ifdouble and tubular werealleles of different genes assorting independently, what phenotypes and genotypes would you observe in the F1 progeny from the cross shown in figure 2?
Draw the cross using the allele abbreviations used in the paper and show the expected phenotype/genotype correlation and ratios. (Hint: write this cross as if the Primrose was a dbl/+; tub/+ dihybrid)
b. Write the genotype of the plants from the F1 you will need to self (cross with themself) to obtain flowers that are double andtubular.
Attachment:- VanGogh-sunflowers-paper.rar