Sequence analysis identified numerous novel alleles and specific motif arrangements, with 113 of the 126 Pfmsp1 block2 allele sequences observed in Dielmo being novel. The RO33 types displayed novel point mutation polymorphisms. Compared to the reported sequences,
the K1 alleles from Dielmo were more diverse (higher number of distinct motifs), with more frequent usage of motifs 3 and 4, and with a novel K1-type motif encoding the SVT tripeptide (7). The Mad20 types were longer (more repeats per allele), used a restricted set of codons and particular motifs, with a higher occurrence of SGG-encoding motifs, more frequent use of motif 8 and fewer motifs 7 and 4. The MR family accounted for up to 13.3% of all Pfmsp1 block2 alleles from Dielmo, a lower frequency
than the 28-29% observed in a Kenyan holoendemic setting [11, 16]. We could #selleck randurls[1|1|,|CHEM1|]# I-BET-762 in vivo not identify any epidemiological parameter associated with the presence of MR alleles: there was no association with age, gender, ABO or Rhesus blood group. Interestingly, like the other three families, MR alleles from Dielmo presented specific characteristics. All harboured a RD5-type RO33 moiety, differing from most MR alleles with a worldwide distribution [11, 16]. Furthermore, DMR1 displayed a novel MR subtype with a 5 7 5 motif (Mad20 sub-group 1c) instead of a 8 7 5 motif (Mad20 Glutamate dehydrogenase sub-group 2c). In addition, a novel hybrid with a 3′ RO33/K1 hybrid sequence was observed. Whether this DMRK allele was generated by insertion of a SPPADA-encoding DNA segment within a MR allele (possibly MR6), or whether this element was inserted within RD5 before recombination with a Mad20 allele is unclear. Insertion of the SPPADA-encoding segment within any allele of the RO33 family has never been reported, but was observed within the K1-type in this study (allele DK67) and in other settings . Observation of a single RO33 progenitor together with a single Mad20 progenitor led Takala et al
 to propose that the MR family arose from a single recombination event. The present data rather suggest that several separate recombination events involving distinct RO33-types and Mad20-types progenitors have contributed to the generation of this hybrid family. The characteristic of the Pfmsp1 block2 allelic repertoire in Dielmo is in line with the epidemiological conditions prevailing in the village. Unlike the surroundings where transmission is moderate and highly seasonal, transmission in Dielmo is perennial and intense . Therefore, local transmission largely dominates over the import of alleles from the neighbouring area during the 9-10 months of the dry season. As such, Dielmo constitutes a transmission area where a high level of genetic diversity can be maintained.