Mutations are changes in the DNA sequence that can occur due to various factors. Here are definitions and examples for each type you've listed:
1. Substitution
Definition: A substitution mutation occurs when one nucleotide in the DNA sequence is replaced with another nucleotide.
Example: In the sequence ATC-GTA, if the A is replaced by G, the new sequence becomes GTC-GTA. This might change the amino acid sequence during translation.
2. Insertion
Definition: An insertion mutation occurs when one or more nucleotides are added to the DNA sequence.
Example: In the sequence ATG-CAT, if an extra G is inserted after the A, the new sequence becomes ATG-GCA-T. This can shift the reading frame.
3. Deletion
Definition: A deletion mutation occurs when one or more nucleotides are removed from the DNA sequence.
Example: In the sequence ATG-CAT, if the C is deleted, the new sequence becomes ATG-AT. This can also shift the reading frame.
4. Silent
Definition: A silent mutation is a change in the DNA sequence that does not alter the resulting amino acid due to the redundancy of the genetic code.
Example: In the sequence GGC (which codes for glycine), if it is changed to GGU, it still codes for glycine, resulting in no change in the protein.
5. Missense
Definition: A missense mutation occurs when a substitution leads to the coding of a different amino acid, potentially altering the protein's function.
Example: In the sequence AAT (which codes for asparagine), if it is changed to GAT, it now codes for aspartic acid instead, altering the protein's properties.
6. Translocation
Definition: Translocation mutations involve the rearrangement of parts of chromosomes where a segment of one chromosome is transferred to another chromosome.
Example: A common example is the Philadelphia chromosome, which results from a translocation between chromosomes 9 and 22, leading to a fusion gene associated with certain leukemias.
Each type of mutation can have different effects on an organism, ranging from neutral to significant impacts on phenotype and health.