Chromosome Probes at the University of Toronto Sensitive chromosome probes recently discovered by a University of Toronto geneticist will make it easier to detect certain types of genetic and prenatal diseases, as well as being used to determine paternity and provide forensic evidence in criminal cases. Probes are short pieces of DNA which bind to, and actually pinpoint, particular sites on a chromosome. Because these new probes are actually repeated hundreds or thousands of time at a particular site, they are much more sensitive than previously available ones. Of the 23 pairs of human chromosomes, Dr. F.H. Willard has discove