Obligate heterodimer meganucleases and uses thereof

An obligate heterodimer meganuclease consisting of a first and a second monomer, deriving from two different parent homodimeric LAGLIDADG (SEQ ID NO:

• 66) endonuclease monomers, and having at least one pair of mutations interesting corresponding residues of said parent monomers which make an intermolecular interaction between the two monomers of each parent homodimeric LAGLIDADG (SEQ ID NO:
• 66) endonuclease, wherein the first mutation of said pair(s) is in the first monomer and the second mutation of said pair(s) is in the second monomer and said pair(s) of mutations impairs the formation of functional homodimers from each monomer without preventing the formation of a functional heterodimer able to cleave a non-palindromic hybrid DNA target comprising one different half of the DNA target cleaved by each parent homodimeric endonuclease.