A genetic mutation is an alteration in the DNA sequence of an organism’s genome. A mutation can lead to a wide range of effects, from no discernible impact to significant changes in an organism’s traits and characteristics. Genetic mutations are a fundamental driver of evolution and are central to the understanding of genetics and inherited traits.
Key points:
Types: Point mutations are small-scale mutations that involve the substitution, addition, or deletion of a single nucleotide in the DNA sequence. Insertions/deletions (Indels) involve the insertion of new nucleotides or the removal of existing ones, which can shift the reading frame and cause significant changes. Chromosomal rearrangements are large-scale mutations that affect the structure and number of chromosomes.
Causes: Spontaneous mutations occur naturally during DNA replication or cell division due to errors in the DNA replication process. Induced mutations are caused by external factors such as radiation, chemicals, and certain environmental influences.
Effects: Silent mutations have no observable impact. Missense mutations result in the substitution of one amino acid for another in the protein encoded by the gene, potentially altering protein function. Nonsense mutations create a premature stop codon, resulting in a truncated, non-functional protein. Frameshift mutations alter the reading frame of the gene, affecting all amino acids downstream.
Inheritance: Somatic mutations occur in non-reproductive cells and are not passed on to offspring. They can lead to diseases like cancer. Germline mutations mutations occur in the reproductive cells (sperm and eggs) and can be inherited by offspring.