Mutations

Mutations are changes that occur in the DNA sequence of a cell's genome. These changes can be caused by errors during DNA replication or other types of damage to DNA, which then may undergo error-prone repair, or cause an error during other forms of repair, or else may cause an error during cell division. Mutations can also be induced by the environment, through exposure to specific chemicals or radiation.

Types of Mutations

Mutations can be classified in several ways, depending on the nature of the change and its effect on the organism.

Point Mutations

Point mutations are changes in a single base pair of a DNA sequence. This can result in a different amino acid being incorporated into a protein, potentially altering its function. Point mutations can be silent, missense, or nonsense mutations.

Insertions and Deletions

Insertions and deletions are mutations in which a section of DNA is added or removed. These mutations can cause a frameshift, which alters the reading frame of the DNA sequence and can significantly change the resulting protein.

Chromosomal Mutations

Chromosomal mutations involve changes to large sections of DNA or entire chromosomes. These can include deletions, duplications, inversions, and translocations.

Effects of Mutations

The effects of mutations can vary widely, from no observable effect to significant changes in an organism's phenotype. Some mutations can cause genetic diseases, while others can provide a survival advantage and drive evolution.

Beneficial Mutations

Beneficial mutations can provide a survival advantage and are often the driving force behind evolution. For example, a mutation that increases an organism's resistance to a disease can increase its chances of survival and reproduction.

Harmful Mutations

Harmful mutations can cause genetic diseases or increase an organism's susceptibility to diseases. For example, mutations in the BRCA1 and BRCA2 genes increase the risk of breast and ovarian cancer.

Mutations and Disease

Many genetic diseases are caused by mutations. These can be inherited from parents or acquired during a person's lifetime. Some examples of genetic diseases caused by mutations include cystic fibrosis, sickle cell anemia, and Huntington's disease.

See Also

• Genetic variation
• Genetic drift
• Natural selection
• Evolution