SKY analysis of

Atm^−/−spleen cells reveals chromosome 14 rearrangements. Inverted DAPI-stained (A) and RGB display images (B) of a representative metaphase from anAtm^−/− mouse splenic T cell. The karyotype is 40, XX, T(12;14). Band analysis indicates that the breakpoint of the translocation is in band 14D. There are 2 normal copies of chromosome 14, so the 14 material in the T(12;14) is a duplication of bands D-E.