Polymorphism of the short tandem repetitive sequences (GGDN) within the DHFR domain of the P. vivax DHFS-TS gene. (1) corresponds to the consensus sequence (amino acid residue 88-106) found in 15 of 30 isolates; (2) is the deleted sequence from isolates PHI/Djibouti and LGF/India. The latter isolates had a silent mutation at the nucleotide level (CAC→CAG); (3) represents the deleted sequence of isolate VAN/Thailand and 11 Burmese isolates; (4) corresponds to the deleted sequence from isolate LFT/Cambodia. Two identical silent mutations (GGT→GGC) and two mutations in 97 (Asn→Lys) and 98 (Thr→Arg) were detected ; (5) corresponds to the deleted sequence from Korean isolates (n = 11). Deletions are denoted by dashes.