Translocation shown using centromere probes

Human chromosomes at metaphase highlighted by fluorescent probes that bind to specific sequences of DNA. Centromere specific probes have been used to determine the break-points in a translocation between the X chromosomes and chromosome 13 (t(x;13). The X signal is red and 13 and 21 centromeres are green. This result shows that the break-point in the long arm of the X is q11. Image by Dr John Crolla.