BIO1102-Optional homework questions on the article “Genetic Analysis of Floral Symmetry in Van...

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BIO1102-Optional homework questions on the article	“Genetic Analysis of Floral Symmetry in Van Gogh's Sunflowers Reveals Independent Recruitment of CYCLOIDEA Genes in the Asteraceae.”You can find the full text article at the link below:http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002628Also, a PDF file is posted on Angel.Please type your answers within the text boxes provided, except when drawing a cross.	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 points)				Brieflyexplain the evolutionary relationship between the two types of flower morphology described in the paper and how they affect pollination and plant diversification.		(3 points)				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.		(3 points)		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.		(2 points)		Why the		tubular		phenotype is not observed in the F1 progeny?		(2 points)		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 (figure 2). 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.		(3 points)				Briefly		describe the DNA alterations found in the two different mutations,		HaCYCc-dblandHaCYCc-tubthat causethe doubleand tubularphenotypes, respectively.		(2 points)				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)(3 points)		State whether		double		is a gain-of-functionor a loss of function mutation and explain your answer		(2 points)		How does the gain and loss of function nature of the		double		and		tubular		mutation correlatesto theirdominant orrecessive behavior(3 points)?Challenge questions for “extra” extra 4 points.The authors state thattubularanddoublearealleles of the same gene because no tubular-double flowers (flowers that show both phenotypes)are observed in the F2 progeny.	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 adbl/+;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.

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BIO1102-Optional homework: 
Due Thursday February 28 Name_________________________________________  
 
BIO1102- Optional homework questions on the article “Genetic Analysis 
of Floral Symmetry in Van Gogh's Sunflowers Reveals Independent 
Recruitment of CYCLOIDEA Genes in the Asteraceae.”  
You can find the full text article at the link below:  
http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002628 
Also, a PDF file is posted on Angel. Please type your answers within the text boxes 
provided, except when drawing a cross.
1) State what is the general biological question that the authors are asking 
by analyzing the double mutant in the sunflower. Briefly explain its 
overall importance to plant biology.  (2 points)
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 points) 
Investigators observed that within Asteraceae, CYC-like genes determine the floral 
symmetry of different plants of this group. Researchers have investigated several 
genes within CYC group including HaCYC2b, HaCYC2c, and HaCYC2e. Also they have 
found that different mutant form of this genes affect differently in the floral 
symmetry of plants. The biological question that the authors are asking by 
analyzing the double mutant is that how subfunctionalization of different paralogs 
within CYC- like gene families has been occurred.  
According to evolutionary evidence it is considered that actinomorphy is ancestral 
while zygomorphy had evolved from actinomorphy. Zygomorph types of floral 
symmetry are more beneficial over actinomorphy because it increases pollinator 
specificity. Thus it induces the evolution of reproductive isolation which plays an 
important role in the diversification of plant life.
http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002628
BIO1102-Optional homework: 
Due Thursday February 28 Name_________________________________________  
 
3) Briefly describe the two different types of florets found in a wild type 
sunflower. Explain how florets morphology and distribution is different 
in double and tubular mutants. (3 points)
4) To generate F1 hybrid offspring, a wild-type plant was crossed with a  
“weak” semi-double mutant (Primrose), which shows an intermediate 
Two tyoes of florets in wild type plants are 
 Actinomorphy: In this floret types flowers are radially symmetrical. 
 Zygomorphy: in this florets type flowers are bilaterally symmetrical. 
         Zygomorphic clades are more speciose than actinomrphy, because zygomorphy 
increases pollination. Thus it is suggested that zygomorphy is evolved from 
actinomorphy and this evolution is very important in plant diversification.
Double mutant are normally actinomorphic disc florets but elongated, outside of the 
florets different from zygomorphic and the center of the inflorescence has slight 
similarity with zygomorphic plants.

BIO1102- Optional homework questions on the article “Genetic Analysis of Floral Symmetry in Van Gogh's Sunflowers Reveals Independent Recruitment of CYCLOIDEA Genes in the Asteraceae.” You can find...

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