615; P < 0.001;

find more Fig. 3A). However, the relationship showed considerably more scatter in the NW ( Fig. 3A) than in the South ( Fig. 3B); as a consequence, there was a significant difference between the two correlation coefficients (2-tailed P = 0.001). We examined polymorphism at four antigen-encoding loci of P. vivax and two of P. falciparum in collections from the NW and South from 2006 to 2007. In the non-repeat regions of P. vivax ama-1, msp1, msp4, and msp5, the numbers of haplotypes and haplotype diversities were strikingly reduced in the South compared to the NW ( Table 1). In every case except msp4, the number of haplotypes was significantly lower in the South than in the NW; and at msp4, there were only two haplotypes in the South, as compared to six in the NW ( Table 1). The relatively low diversity

at msp4 is consistent with relatively low diversity at this locus elsewhere in the world [22]. Moreover, at all four P. vivax loci, the haplotype diversity was significantly lower in the South than in the North ( Table 1). At the csp and msp2 loci of P. falciparum, both the number of haplotypes and the haplotype diversity were significantly reduced in the South in comparison to the NW ( Table 1). In fact there was only a single haplotype in the non-repeat region of msp2 in the South. Alleles at msp2 of P. falciparum fall into two click here very distinctive allelic families, designated 3D7

and FC27, which have very divergent sequences both in the repeats and in portions of the non-repeat region [10]. Only the 3D7 family was found in 82 sequences sampled from the South. In P. vivax, nonsynonymous nucleotide diversity (πN) in non-repeat regions was significantly lower in the South than in the NW at all loci except msp4 ( Table 2). In P. falciparum, πN at csp was significantly lower in the South than in the NW ( Table 2). Only the 3D7 family of P. falciparum msp2 alleles was found in both NW and South, and there were no synonymous or nonsynonymous polymorphisms at this locus in the South ( Table 2). Among the 3D7 family alleles at msp2 in the NW, πN was significantly greater than zero and thus significantly than the value for the South ( Table 2). At msp1 of P. vivax, synonymous nucleotide diversity Resminostat (πS) was significantly lower in the South than in the NW ( Table 2). The other loci examined did not show significant differences between NW and South with respect to πS, but πS in the NW was in every case greater than or equal to that in the South ( Table 2). Reduction of diversity in sequences from the South was seen in repeat regions as well as non-repeat regions. For example, of the 88 P. falciparum msp2 sequences from the South, all of which had the same haplotype in the non-repeat regions, only two showed distinct sequences in the repeat regions.