Is this an example of epistasis? And my hypothesis for this box is phenotype to
ID: 142834 • Letter: I
Question
Is this an example of epistasis? And my hypothesis for this box is phenotype to be 13:3 and genotype to be 9:3:3:1. A true-breeding maize line with the color inhibitor gene and the gene for colored aleurone (C'C'RR), which thus had uncolored aleurone and yellow endosperm, was crossed to a true-breeding strain with the color gene, which was recessive for the r allele (CCrr) so the aleurone of this strain was also uncolored allowing the yellow endosperm to show through. The F1 had yellow kernels as well. These were selfed and you have the results of this cross. What is your proposed phenotypic and genotypic ratio for the offspring (kernels) of this cross?Explanation / Answer
C'C'RR x CCrr
Epistasis seems to be the case because the C gene is controlling the expression of R gene.
First we split the two lines into all possible gametes, randomly.(Mendel's law of independent assortment).
C'R
C' being the dominant gene will show yellow colour wherever it is present(C'C',C'C) and R being the dominant gene will give colored aleurone (Rr.RR) unless it is suppressed by C'.
The Y genotypes are the ones with yellow colour. Your hypothesis seems to be coreect becaus the phenotypic ratio is 13 : 3 in favor of Yellow.
However the genotypic ratio is
C'C'RR : C'CRR : CCRR: C'C'Rr : C'CRr : CCRr : C'C'rr : C'Crr : CCrr =
1 : 2 : 1 : 2 : 4 : 2 : 1 : 2 : 1
Your Genotypic ratio seems to be incorrect because most of the genotypes are different while in phenotype it can be either Yellow or not.
The table will clear most of your doubts, look at it carefully.
Please give this answer a good rating. Thank You.
C'R
C'C'RR(Y) C'C'Rr(Y) C'CRR(Y) C'CRr(Y) C'r C'C'Rr(Y) C'C'rr(Y) C'CRr(Y) C'Crr(Y) CR C'CRR(Y) C'CRr(Y) CCRR CCRr Cr C'CRr(Y) C'Crr(Y) CCRr CCrr(Y)Related Questions
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