Gene conversion is a recombination transfer between DNA sequences. The converting gene is unaltered, but the gene receiving the DNA transfer may well be mutated by the process.
Gene conversion happens at high frequencies during meiotic division, but also occurs in somatic cells, notably immune system cells. Gene conversion lies outside Mendelian inheritance.
Gene conversion tends to homogenize the DNA in the gene pool of a species. A gene conversion takes 2 similar-but-different DNA because of sequence mismatches and yields 2 identical DNA sequences.
Gene conversion is a cohesive force linking DNA sequences within different organisms of a species. Over time, absent other dynamics, gene conversion would yield a homogenous set of DNA.
Gene conversion is not random. Biased gene conversion (BCG) – where a certain allele is favored – is quite common. BCG can selectively accelerate evolution in certain genes, increasing the rate at which specific mutations spread through a population. BCG is often strongest in genetic regions prone to high recombination rates.