Mismatch distribution of Plasmodium vivax circumsporozoite central repeat sequence: average p versus σ (p). Average p and its variance (σ (p)) clearly cluster central sequences and separate vk247 from vk210 sequences. One worldwide group formed by vk247 parasites with the highest average p and σ (p). Latin American (LA) isolates had a csp central repeat of lower average p than sequences from outside America (OA; other geographic origins). LA isolates were further separated in two groups by their p variance, one with lower σ (p) (C1A; Sal I, Honduras III, Mxch3-vk210aI, Nichn, Nir1-vk210aIII) than the other (C1B; Mxch13-vk210aII, Nichg). The latter was separated by the average p from the OA isolates (C2; Mxch4-vk210b, Mxch3-vk210c). C2 is composed by a tight group and others of higher average p and σ (p) were scattered (see also Additional files 1 and 2). Mxch14-vk210d and P. simium I are marginal between LA and OA isolates. The Mexican vk210b, c and d are indicated by arrows. 1P. simium I and 2P. simium II.