Point mutation

A point mutation, or single base modification, is a type of mutation that causes a single nucleotide base change, insertion, or deletion of the genetic material, DNA or RNA. The term frameshift mutation indicates the addition or deletion of a base pair.

A point mutant is an individual that is affected by a point mutation.

Repeat induced point mutations are recurring point mutations, discussed below.

Causes of point mutations

Point mutation is a random SNP (single-nucleotide polymorphism) mutation in the deoxyribonucleic acid (DNA) that occurs at one point. Point mutations usually take place during DNA replication. DNA replication occurs when one double-stranded DNA molecule creates two single strands of DNA, each of which is a template for the creation of the complementary strand. A single point mutation can change the whole DNA sequence. Changing one purine or pyrimidine may change the amino acid that the nucleotides code for.

Point mutations may arise from spontaneous mutations that occur during DNA replication. The rate of mutation may be increased by mutagens. Mutagens can be physical, such as radiation from UV rays, X-rays or extreme heat, or chemical (molecules that misplace base pairs or disrupt the helical shape of DNA). Mutagens associated with cancers are often studied to learn about cancer and its prevention.