- What is the amino acid sequence encoded by the DNA sequence?
The DNA sequence given is: GCATGCTGCGAAACTTTGGCTGA
The 3-letter codons are: ATG CTG CGA AAC TTT GGC TGA
The amino acid sequence is: Met Leu Arg Asn Phe Gly Stop
- What does a missense mutation look like?
Here's one example: GCATGGTGCGAAACTTTGGCTGA
The 3-letter codons are: ATG GTG CGA AAC TTT GGC TGA
The amino acid sequence is: Met Val Arg Asn Phe Gly Stop
- What does a nonsense mutation look like?
Here's one example: GCATGCTGTGAAACTTTGGCTGA
The 3-letter codons are: ATG CTG TGA AAC TTT GGC TGA
The amino acid sequence is: Met Leu Stop
- You can make more than one frameshift mutation. What do they look like?
How do they change the amino acid sequence? Here are some examples of different
frameshift mutations.
Insertion: GCATGCTGATCGAAACTTTGGCTGA
The 3-letter codons are: ATG CTGATC GAA ACT TTG GCT GA
The amino acid sequence is: Met Leu Ile Glu Thr Leu Ala
Deletion: GCATGCT-CGAAACTTTGGCTGA
The 3-letter codons are: ATG CTC GAA ACT TTG GCT GA
The amino acid sequence is: Met Leu Glu Thr Leu Ala
Insertion: GCATGCTGAAAGATAGTTGTCGAAACTTTGGCTGA
The 3-letter codons are: ATG CTG AAA GAT AGT TGT CGA AAC TTT GGC TGA
The amino acid sequence is: Met Leu Lys Asp Ser Cys Arg Asn Phe Gly
Deletion: GCATGCTGCG-----TTGGCTGA
The 3-letter codons are:ATG CTG CGT TGG CTG
The amino acid sequence is: Met Leu Arg Trp Leu
- Notice how a single amino acid can be encoded by a number of different codons. What are some examples of silent mutations in the DNA sequence?
Here's one example: GCATGCTGCGTAACTTTGGCTGA
The 3-letter codons are: ATG CTG CGT AAC TTT GGC TGA
The amino acid sequence is: Met Leu Arg Asn Phe Gly Stop
A silent mutation changes a nucleotide without changing the codon. For many amino acids the third nucleotide of the codon can be variable. For example, CCT, CCC, CCA and CCG all code for Proline. However, for some amino acids, both the first and the third nucleotide of the codon can vary. For example, CTT, CTC, CTA, TTA, CTG, AND TTG all code for Leucine.
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