Cytogenetic analysis of the UKE-1 cell line used in this experiment. We observed two clones and determined the karyotype to be 46,XX,-7,+8,del(11)(p1?1p1?3),del(20q)[12]/92,idemx2,del(9) (q2?1)[8]. (a) RHG banding of the pseudo-diploid clone. (b) RHG banding of the tetraploid clone. Note the partial deletion of the long arm of chromosome 9. (c) FISH-BAC analysis on the UKE-1 cell line using a JAK2 probe labeled with spectrumGreen and a reference probe on 9p21.2 labeled with spectrumOrange. The metaphase FISH shows five copies of JAK2 in the tetraploid clone: three normal chromosomes 9, each having one copy of JAK2 (green) and a chromosome 9 derivative having two copies of JAK2.