Nucleotide sequence encoding the enzyme I-SceI and the uses thereof

A method for introducing a double-stranded break into a target nucleic acid sequence in a plant or animal cell comprising:

• providing an isolated plant or animal cell comprising a Group I intron encoded endonuclease recognition site in a target nucleic acid and
• providing the Group I intron encoded endonuclease to the cell by genetically modifying the cell with a nucleic acid comprising said Group I intron encoded endonuclease or introducing said Group I intron encoded endonuclease protein into the cell such that the endonuclease cleaves the endonuclease site in the target nucleic acid sequence,
• wherein the site is selected from the group consisting of an I-SceIV site, an I-CsmI site, an I-PanI site, an I-SceII site, an I-CeuI site, an I-PpoI site, an I-SceIII site, an I-CreI site, an I-TevI site, an I-TevII site, an I-TevIII site, and an I-SceI site.