Essay On Mutation

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Spontaneous mutations occur during a normal cell process creating genetic changes (text p.206). There are varying types of spontaneous mutations including, silent, missense, nonsense, and frameshift mutations. How are these mutations the same and how are they different? Silent, missense, and nonsense mutations all occur when base substitutions happen (text p.206). A base substitution is when the wrong nucleotide is incorporated during DNA synthesis, this is the most common mutation (lecture). In a silent mutation a base substitution occurs, incorporating an incorrect nucleotide, the result is a codon that codes for an amino acid that is the same as the wild type (text p. 206). In a missense mutation, the resulting mutant codon does not…show more content…
These mutations are ones that often produce stop codons, putting a halt to the creation of the protein with shortened amino acid sequences. They may also generate proteins that do not function. By simply adding a single nucleotide you alter the coding outcomes of the remaining nucleotides down the sequence. If one were to insert a sequence of three nucleotides, they would be inserting a complete amino acid. Because of this, there is a higher likelihood that the sequence of three nucleotides would simple produce a new amino acid, rather than a stop codon, unless it itself was a stop codon. This creation of a new amino acid to the sequence would elongating the genetic sequence and continue to produce a functioning protein while allowing the remaining gene sequence to remain the same. Example 1.1: Insertion into a reading frame:

Reading Frame 1: Wild Type


Met Leu Ser Tyr Ile STOP

The above frame demonstrates gene sequence with start and stop codons.

Reading Frame 2: Single Insertion:


Met Leu Ser STOP Tyr Leu The above frame demonstrates gene sequence with the insertion of a single nucleotide, resulting in a stop codon.

Reading Frame 3: 3 Nucleotide Insertion:


Met Leu Ser Pro Tyr Ile Stop

The above frame
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