Familial aniridia deletion shown by cosmid

Chromosomes from a patient with isolated familial aniridia. The chromosomes have been made fluorescent with probes that bind to specific sequences of DNA. A cosmid probe F02121 (red) shows up the deletion in chromosome 11, and a green fluorescent probe shows up the chromosome 11 centromeres. This condition involves the developmental absence of most of the iris. Its base is present on the ciliary body, and often upsets the aqueous outflow mechanism. Also called irideremia. Image by Dr John Crolla.