Käänteismutaatio

Käänteismutaatio, also known as reverse mutation or back mutation, is a genetic alteration in which a mutated gene or DNA sequence returns to its original, wild-type state. This can occur through a second mutation event that either directly reverses the original mutation or restores the original DNA sequence through a different mechanism. For example, if a single nucleotide substitution caused a mutation, a subsequent substitution at the same site could revert it back to the original nucleotide. Alternatively, if a deletion or insertion occurred, a reverse mutation could be an insertion or deletion that restores the original reading frame or gene function.

Reverse mutations are important in understanding gene function and the nature of mutations. They can be used to identify the specific codons or DNA regions responsible for a particular trait or phenotype. Studying reverse mutations helps researchers map genes and understand the mechanisms of DNA repair and mutation. While a reverse mutation can restore the original phenotype, the DNA sequence may not always be identical to the original wild-type sequence. For instance, if the original mutation was a frameshift caused by a single base deletion, a reverse mutation might involve the insertion of a different base pair that restores the reading frame, but the sequence itself is still altered.