Mutation
Introduction
Mutations are changes in the DNA sequence that can affect genetic information. They play a crucial role in evolution, genetic diversity, and can lead to various diseases.
Types of Genetic Mutations
Point Mutations
- Definition: A change in a single nucleotide base in the DNA sequence.
- Examples:
- Silent Mutation: No change in the amino acid sequence.
- Missense Mutation: Alters one amino acid in a protein.
- Nonsense Mutation: Creates a premature stop codon.
Insertions
- Definition: Addition of one or more nucleotide bases into the DNA sequence.
- Effect: Can disrupt the reading frame, leading to a frameshift mutation.
Deletions
- Definition: Removal of one or more nucleotide bases from the DNA sequence.
- Effect: May cause a frameshift if the number of deleted bases is not a multiple of three.
Frameshift Mutations
- Definition: A shift in the reading frame of the genetic code due to an insertion or deletion.
- Effect: Alters the entire amino acid sequence downstream of the mutation, often resulting in a nonfunctional protein.
Comparison of Mutation Types
| Mutation Type | Example Sequence (Original: ATG CGA TGC) | Altered Sequence |
|---|---|---|
| Point Mutation | ATG CGA TGC | ATG CGA AGC |
| Insertion | ATG CGA TGC | ATG CGA TA TGC |
| Deletion | ATG CGA TGC | ATG CA TGC |
| Frameshift | ATG CGA TGC | ATG CGA TA GC |
Conclusion
Mutations are fundamental to genetic variation and can have significant biological consequences. Understanding the types of mutations helps in diagnosing genetic disorders and developing therapeutic strategies.
References
- Alberts, B. et al. (2014). Molecular Biology of the Cell. Garland Science.
- Lodish, H. et al. (2016). Molecular Cell Biology. W.H. Freeman.
- Cooper, G. M., & Hausman, R. E. (2013). The Cell: A Molecular Approach. Sinauer Associates.
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