Nucleotide diversity and Tajima’s D value across the DBLMSP1-1 genotype in global P. falciparum populations. (A) Sliding window analysis of nucleotide diversity (π) for DBLMSP1-1 across samples from 14 countries. Diversity is lowest in the Duffy-binding domain (~553–930 bp) and SPAM domain (~1624–2088 bp), and highest within the central modular region. (B) Tajima’s D shows regional variation: values near zero within the receptor-binding domain indicate neutrality or purifying selection, whereas surrounding modules exhibit elevated D values, positive in Asian populations but negative in African populations, suggesting differences in selective pressure. The modular map below corresponds to the aligned sequence scale, showing conserved regions (gray), hypervariable modules (A–E), and structural domains.