chromosome transfer technique
Mouse cell lines that contain one human chromosome (red) are induced to form micronuclei. Each micronucleus contains a few chromosomes, some with and some without the human chromosome. The micronuclei are isolated and fused with the patient cell line. After selection, only the patient cell lines that contain the donor human chromosome survive. This method has been succesfully used to identify the SURF1 gene that is defective in a form of Leigh syndrome.