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    Two example problems for genetics students

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    6) Mutational changes were introduced in a single codon in the gene of T4 phage. The following amino acid substitutions were observed. By following the base changes in the codons determine the codon for each mutant. Assume each amino acid substitution resulted from a single base substitution. Codons for several amino acids are provided: UAG, UAA, and UGA are stop codons. No additional information is required to solve this problem.

    7) A red kernel wheat plant is crossed with a white kernelled plant yielding F1 plant all red kernels. A self cross yields a 15:1 red: white ratio. A testcross yields a 3:1 ratio red: white ratio. Explain the results. Draw Punnet Squares for both the self and the test cross.

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    https://brainmass.com/biology/genetics/genetics-mutation-punnet-square-problems-392761

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    Hi there,

    Please find the attached word document with an explanation of your questions. I hope they help you out with your genetics course!

    The codons marked in red are the correct answers. Here is how to determine the correct codon for each mutant:
    Step 1: Compare the Mutant A codon (UGG) with the normal ser-codons.
    The question tells you that you have a single base substitution occurring. Therefore, look at UGG and determine how to you can create any of the normal codons listed by changing ONE base pair only. UGG can ONLY become UCG. All of the other choices would require a change in two or more base pairs.

    Step 2: Determine ...

    Solution Summary

    This solution provides two completed sample genetics problems regarding mutations using punnet squares.

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