In 1973, Janet Rowley in Chicago showed that the Philadelphia chromosome had originated through a translocation between chromosomes 9 and 22, and not through a simple deletion of chromosome 22 as was previously thought.
En 1973, Janet Rowley en Chicago demostrou que o cromosoma Filadelfia se orixinara por medio dunha translocación entre os cromosomas 9 e 22, e non por medio dunha simple deleción do cormosoma 22, como se pensara inicialmente.