Definition:
A genetic mutation is a permanent alteration in the DNA sequence of an organism’s genome. These changes can occur due to errors during DNA replication, exposure to environmental factors, or as a result of viral infections. Mutations can affect a single nucleotide or large segments of chromosomes.
Types of Genetic Mutations:
- Point Mutation: A change in a single nucleotide base pair in the DNA sequence. This can be further classified into:
- Substitution: One base is replaced by another, which may or may not change the resulting protein.
- Silent Mutation: A substitution that does not alter the amino acid sequence of the protein.
- Missense Mutation: A substitution that results in a different amino acid being incorporated into the protein.
- Nonsense Mutation: A substitution that creates a premature stop codon, leading to an incomplete and usually nonfunctional protein.
- Insertion: One or more extra nucleotides are added into the DNA sequence, which can lead to a frameshift mutation if it alters the reading frame of the gene.
- Deletion: One or more nucleotides are removed from the DNA sequence, which can also cause a frameshift and potentially disrupt protein production.
- Chromosomal Mutations: Larger-scale mutations that affect whole segments of chromosomes, including:
- Duplication: A segment of DNA is copied, leading to multiple copies of a gene. Inversion: A segment of DNA is reversed within the chromosome.
- Translocation: A segment of DNA is moved from one chromosome to another. Deletion: A segment of DNA is lost from the chromosome.
Causes of Genetic Mutations:
Genetic mutations can arise from various sources:
- Spontaneous Errors: Mistakes made during DNA replication when cells divide.
- Environmental Factors: Exposure to radiation, chemicals, or viruses that can damage DNA.
- Inherited Mutations: Mutations that are passed down from parents to offspring through germline cells (sperm and eggs).
