Gene synteny in species of Plasmodium.

We have attempted to establish the degree of linkage conservation between different species of the malaria parasite Plasmodium. Initially, the chromosome locations of 42 homologous genes were established in parasites from a rodent malaria species and the human malaria parasite P. falciparum. Of these genes, 26 appeared to be conserved within ten synteny groups between the two genomes. Several synteny groups were analysed further by long-range restriction mapping of digested chromosomes. Finally, a fine restriction map of one of the linkage groups was made from the rodent malaria parasites P. berghei and from P. falciparum and from the simian malaria parasite P. knowlesi. The fine-scale organisation of this linkage group appears to have remained intact among the three species, despite the evolutionary distance between them. This provides the first example of linkage conservation between the rodent, simian and human malaria species, which represent three different branches of the inferred phylogenetic tree of the genus Plasmodium.