Cre-Lox recombination is a special type of site-specific recombination. The Cre protein is a site-specific DNA recombinase. It can catalyze the recombination of DNA between specific sites in a DNA molecule. These sites, known as loxP sequences, contain specific binding sites for Cre that surround a directional core sequence where recombination can occur. It is often used in the generation of knockout and conditional knockout animals.