9. A homozygous strain of yellow corn is crossed with another homozygous strain
ID: 186979 • Letter: 9
Question
9. A homozygous strain of yellow corn is crossed with another homozygous strain of yellow corn producing a purple Fi progeny. The Fi plant is self-crossed, producing an ear of corn with 174 purple kernels and 139 yellow kernels (the progeny). (7 points) a. Propose a hypothesis for the pattern of inheritance and test with chi square analysis. b. Define your own gene symbols and give the genotypes of the Pt, Fi, F2 generations C. Give a cellular explanation of how the purple color cornm plant is derived. d) If instead of the above cross, a researcher mates two yellow mice with straight hair and obtains the following progeny i. 6/12 yellow, straight hair ii. 2/12 yellow, fuzzy hair enal nhevitance iii. 3/12 gray, straight hair iv. 1/12 gray, fuzzy hair How would you explain the mode of inheritance of the yellow and hair alleles? Include branch diagram and calculation to show how you arrived at your explanation. (3 points)Explanation / Answer
9a. In corn the colur of the carnels may be ywllow or purple. And the the purple is dominant over the yellow so it is likel y that when you you cross 2 heterozygous yellow corn the F1 corns will be purple and yellow in3:1 ratio. But here both the corns are homozygous for the the colour yellow and the corns do not bear any gene for the purple. To explain this hypothesis iwe can say that some epistatic effect might be playing some role.Another hypothesis could be the color of the corn is inheritedby more than one gene i.w. multigenic inheritance.
b. P1 rr * rr
F1 Rr * Rr
F2 RR, Rr, rr
R - Purple
r Yellow.
c. As I have already mentioned in this case only multigenic inheritance of clor gene could be an explanation for this result.
d.
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