Emäsparivirheitä

Emäsparivirheitä, or base pair mismatches, are errors that occur during DNA replication or repair where an incorrect nucleotide is incorporated into a DNA strand. Instead of the standard A pairing with T and G pairing with C, a mismatch involves a non-canonical pairing, such as A with G or C with T. These errors can arise spontaneously due to the inherent chemical instability of nucleotides or be induced by external factors like radiation or certain chemicals.

The consequences of base pair mismatches depend on their location and whether they are repaired. If a mismatch is not corrected, it can lead to a point mutation when the DNA is replicated again. This means that a permanent change in the DNA sequence occurs. Such mutations can have a range of effects, from being silent (having no impact on protein function) to causing significant alterations in gene expression or protein structure, potentially leading to diseases like cancer.

Fortunately, cells possess sophisticated DNA repair mechanisms that detect and correct most base pair mismatches. Mismatch repair systems actively scan the newly synthesized DNA for errors and excise the incorrect nucleotide, allowing DNA polymerase to insert the correct one. This proofreading ability is crucial for maintaining the integrity of the genome and preventing the accumulation of mutations. The efficiency of these repair systems is vital for cellular health and organismal survival.