Fig. 3. Examples of BOX polymerase chain reaction (PCR) fingerprint patterns of rhizobial isolates. Molecular size markers of lambda DNA digested with Hind III and Eco RI are: Lanes 1, 12, and 42 in Gel A, and 1 and 25 in Gel B. All the other lanes are BOX-PCR fingerprint patterns of clover rhizobia isolated from low metal polluted soil (Gel A) or high polluted soil (Gel B).