Process in genetics that describes the duplication of a specific gene or a specific DNA segment on one of the two sister chromatids created during replication by unequal crossing over. A distinction is made here between partial and complete gene duplication.
Gene duplications are the starting point for the formation of gene families. As a rule, the mutations cannot be corrected by their own repair mechanisms and often lead to congenital defects due to the severe alteration of the gene sequence. However, gene duplication is also considered to be an essential mechanism of evolution.