Recombination
Recombination is the rejoining and breaking of DNA strands to form latest molecules of DNA encoding a novel collection of genetic information. Recombination can occur among same molecules of DNA as in the homologous recombination of dissimilar molecules or chromosomal crossover, as in non-homologous end joining. A recombination in organisms with an adaptive immune system is a kind of genetic recombination which helps immune cells rapidly diversifies to adapt and recognize to new pathogens. Recombination is a general technique of DNA repair in both eukaryotes and bacteria.
Genetic recombination is catalyzed through several different enzymes that are called recombinases. A RecA the chief recombinase found in Escherichia coli is responsible for the repair of DNA double strand breaks. In other eukaryotic organisms and yeast there are two recombinases needs for repairing DSBs. The RAD51 protein is needed for meiotic and mitotic recombination whereas the DMC1 protein is exact to meiotic recombination.