Nucleotide sequence types of the P. vivax msp1 icb5-6 polymorphic fragment of Mexican isolates. Five different sequence types were constructed according to its homology to the reference strains: gene fragment of Sal I (XM001614792; 2035–2760 nt) and of Belem (AF435594; 2047–2709 nt) strains. Blank boxes are partially conserved subfragments. Black and grey boxes are polymorphic subfragments. Eight-linked nucleotide changes within 33 nt were conserved in 5′C end of sequence type B. Belem domains (compared to Sal I sequence, three and six linked changes within 21 nt each at sV2 in isolates Mx82 and mx83, respectively). Other common nucleotide changes are indicated with dashes and letters. Based on subfragment sV1, three main sequence types are indicated: B (Belem), S (Sal I) and H (Sal I-Belem). nt, nucleotide.