Figure 1. Classification of var-DBL1α transcript sequences of Yunnan isolates in comparison with other field isolates and 3D7 strain.

(A) DBL1α amino acid sequences derived from cDNA were divided into six sequence groups in terms of the conserved “cysteine/PoLV” sequence tag within the DBL1α region. The distribution of different subsets of individual isolate and overall cDNA sequences (A_all) of the 9 Yunnan isolates were shown in each bar with 3D7 strain (genomic sequence) as reference. The 95% confidence values (p) for the χ ² test between DBLα1 (subgroup 1∼3) and others was: p<0.01*. (B) The distribution of each subgroups of DBL1α sequence (cDNA) based on the number of cysteines in Yunnan symptomatic malaria isolates were analyzed with 3D7 (gDNA), Africa (cDNA) and global sequences (cDNA) as references. The subgroup var genes were labeled as follows: red, cys2 (DBLα1); green, cys4 (DBLα); white, cysX (else).