Figure 2. Restriction fragment length polymorphism analysis of H1 products amplified with multiplex-nested primer set from seropositive sera. Ethidium bromide–stained polyacrylamide gels of AluI restriction endonuclease digestion of ≈420 bp rickettsial DNA amplified by using the nested primer H set WJ77/80 in the primary reactions and WJ79/83/78 in the nested reactions. Lanes: M, size marker DNA (25-bp DNA ladder); 1–18: H1–H18; 19–23: H20–24; C, R. conorii; A, R. akari; J, R. japonica; F, R. felis. J–S; predicted fragments after digestion. The number on the left indicates the molecular size (in base pairs) of restriction fragments.