FOLATE SENSITIVE COMMON FRAGILE SITES IN CHROMOSOMES OF THE DOMESTIC PIG (SUS-SCROFA)

Chromosomal fragile sites were studied in blood lymphocytes of the pig after induction with 0, 5, 10 and 20 mug of fluorodeoxyuridine (FudR) ml-1 of culture. The percentage of cells showing fragile sites and to tal breaks and gaps in 100 cells was significantly higher in all treat ed cultures than the control (P<0.001). A concentration of 5 to 10 mug of FudR ml-1 of medium is recommended as the optimum for mitotic inde x and fragile site expression in the pig. Localisation of the fragile sites was by GTG banding after destaining of the conventionally staine d Giemsa preparations. Common fragile sites in the pig were identified in 24 sites on 10 chromosomes. Some fragile sites corresponded to the breakpoints in known reciprocal translocations.