Common fragile sites in man and three closely related primate species.

The expression of common fragile sites was studied in peripheral lymphocytes of man, gorilla, chimpanzee, and orangutan after induction with aphidicolin, methotrexate, or fluorodeoxyuridine. As far as the chromosomal localization is concerned, it appears that many of these sites have been highly conserved during primate evolution. However, differences were found in the relative expression of certain sites. In all four species, mapping of approximately 500 lesions disclosed the most breakage-prone common fragile sites, at which about 90% of all induced aberrations were localized. Comparison of chromosome regions involved in evolutionary changes to fragile sites in the four primate species revealed 30 sites that were located at or close to the same chromosomal band. However, no correlation was found between the relative expression of a certain common fragile site in vitro and a potential involvement of this chromosomal site in evolutionary changes.