Gene mutation types and point mutations in DNA and mRNA sequences.

Problem Analysis

The task involves identifying different types of gene mutations in DNA sequences and classifying them into specific categories. The mutations include frameshift insertion, frameshift deletion, and substitution. Additionally, the task requires identifying whether the mutations are missense, nonsense, or silent point mutations.

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Step-by-Step Solution

#### Part 1: Identifying Frameshift Insertion, Frameshift Deletion, and Substitution

1. Normal (Unmutated) Sequence:
- DNA: `AAA ATG CTT CTC`
- mRNA: `UUU UAC GAA GAG`
- Amino acids: `Phe Tyr Glu Glu`

2. First Mutated Sequence:
- DNA: `AAA ATG TTT CTC` (extra `T` inserted after `ATG`)
- mRNA: `UUU UAC AAA GAG`
- Amino acids: `Phe Tyr Lys Glu`
- Explanation: An extra nucleotide (`T`) has been inserted, shifting the reading frame. This is a frameshift insertion.
- Answer: Frameshift insertion

3. Second Mutated Sequence:
- DNA: `AAA ATG CTT CTC` (no change)
- mRNA: `UUU UAC GGA AGA`
- Amino acids: `Phe Tyr Gly Arg`
- Explanation: The DNA sequence remains unchanged, but the amino acid sequence has changed due to a substitution in the mRNA. This is a substitution.
- Answer: Substitution

4. Third Mutated Sequence:
- DNA: `AAA ATG CTT CTC` (no change)
- mRNA: `UUU UAC GGU AAG`
- Amino acids: `Phe Tyr Gly Arg`
- Explanation: Similar to the second sequence, the DNA sequence is unchanged, but the amino acid sequence has changed due to a substitution in the mRNA. This is another substitution.
- Answer: Substitution

5. Fourth Mutated Sequence:
- DNA: `AAA TGC TTU ACA` (one nucleotide deleted after `AAA`)
- mRNA: `UUU ACU AUG AAU`
- Amino acids: `Phe Thr Lys Arg`
- Explanation: A nucleotide (`A`) has been deleted, shifting the reading frame. This is a frameshift deletion.
- Answer: Frameshift deletion

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#### Part 2: Identifying Missense, Nonsense, and Silent Point Mutations

1. Original Strand:
- DNA: `G A U G C C G U A U U A C G U A C C U U A A A U C G...`
- mRNA: `Met Pro Tyr Tyr Val Pro STOP`
- Explanation: This is the reference sequence for comparison.

2. First Mutated Strand:
- DNA: `G A U G C C G U A U U A C G U U C C U U A A A U C G...`
- mRNA: `Met Pro Tyr Tyr Val Pro STOP`
- Explanation: The mutation changes `C` to `U`, resulting in a different codon (`GUC` instead of `GUA`). However, both codons code for the same amino acid (`Val`). This is a silent mutation.
- Answer: Silent mutation

3. Second Mutated Strand:
- DNA: `G A U G C C G U A U U A C G U A C C U U A A A U C G...`
- mRNA: `Met Pro Tyr Tyr Val Pro STOP`
- Explanation: The mutation changes `A` to `G`, resulting in a different codon (`GUG` instead of `GUA`). Both codons still code for the same amino acid (`Val`). This is another silent mutation.
- Answer: Silent mutation

4. Third Mutated Strand:
- DNA: `G A U G C C G U A U U A C G U A C C U U A A A U C G...`
- mRNA: `Met Ser Tyr Tyr Val Pro STOP`
- Explanation: The mutation changes `U` to `C`, resulting in a different codon (`UCG` instead of `UCU`). This leads to a different amino acid (`Ser` instead of `Pro`). This is a missense mutation.
- Answer: Missense mutation

5. Fourth Mutated Strand:
- DNA: `G A U G C C G U A U U A C G U A C C U U A A A U C G...`
- mRNA: `Met Pro Tyr STOP`
- Explanation: The mutation changes `A` to `G`, resulting in a stop codon (`UGA`). This prematurely terminates translation. This is a nonsense mutation.
- Answer: Nonsense mutation

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Final Answers

#### Part 1:
1. Frameshift insertion
2. Substitution
3. Substitution
4. Frameshift deletion

#### Part 2:
1. Silent mutation
2. Silent mutation
3. Missense mutation
4. Nonsense mutation

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Boxed Final Answer:

\[
\boxed{
\begin{array}{l}
\text{Frameshift insertion} \\
\text{Substitution} \\
\text{Substitution} \\
\text{Frameshift deletion} \\
\text{Silent mutation} \\
\text{Silent mutation} \\
\text{Missense mutation} \\
\text{Nonsense mutation}
\end{array}
}
\]