Patent Document ID: 6077667
Application ID: 08883616
Patent Flag: 1

Claim One:
1. A method for deleting a selected region of genetic material in cells comprising the steps of: inserting a first selection cassette at a 5' end of said selected region using conventional gene targeting methods, said first selection cassette comprising a first selectable marker, a first loxP recombination site, and a first portion of a second selectable marker; selecting cells expressing said first selectable marker; inserting a second selection cassette at a 3' end of said selected region using conventional gene targeting methods, said second selection cassette comprising a third selectable marker, a second loxP recombination site, and a remaining portion of said second selectable marker; expressing Cre recombinase to produce recombination between said first and second loxP sites; and selecting cells expressing said second selectable marker, wherein the selected region of genetic material is deleted.