FISH analysis of truncated human chromosome 3 in DT40 cells. Upper panels show representative metaphase spreads (A-D) and bottom panels show the enlarge image of human chromosome with allow. The allow shows a targeting site on chromosome 3 using biotin-labeled PGK-puro probe (green color). (A) DT40 containing an intact human chromosome 3. (B) DT40 containing #3delp24-pter. (C) DT40 containing #3delp22-pter. (D) DT40 containing #3delp21.3-pter. Digoxigenin-labeled human COT-1 probe (red color) indicates human chromosome. DAPI staining (blue color) shows chicken chromosomes.