génváltások

Génváltások, also known as gene conversions, are a type of genetic recombination where one sequence of DNA is replaced by a homologous sequence from another DNA molecule. This process can occur during meiosis, the cell division that produces gametes, or during mitosis, the process of cell division for growth and repair. Unlike crossing over, which involves an exchange of segments between homologous chromosomes, gene conversion results in an allele on one chromosome being changed to match the allele on its homologous partner.

The mechanism of gene conversion typically involves DNA double-strand breaks. A break in one DNA duplex can be repaired using the intact homologous duplex as a template. During this repair process, a segment of the donor DNA can be copied into the broken recipient DNA. If the homologous sequences differ in allelic states, this templated repair can lead to the conversion of one allele into another.

Gene conversion plays a significant role in evolution and genetic diversity. It can help to homogenize sequences within a gene family, preventing the accumulation of deleterious mutations. It is also implicated in the generation of genetic variation, although it primarily acts to correct differences rather than create new ones. In some organisms, gene conversion is a common event, while in others it is less frequent. Studies of gene conversion patterns can provide insights into the history of gene family evolution and the mechanisms of DNA repair.