Genomic Evolution

Comparative genomics allows inferences to be drawn about the coding potential of related genomes, and the evolutionary forces that have influenced genome organization. In 2 researches that compare the genome of Plasmodium falciparum with Plasmodium berghei and Plasmodium yoelii yoelii by Thompson et al. (2001) and Carlton et al. (2005) respectively, which both are malaria parasites of rodents, both indicate there are striking conservation of gene synteny (conserved physical association of genes) between malaria species within conserved chromosome cores. They also found that genes that elicit a host immune response are frequently found to be species-specific, although a large variant multigene family is common to many rodent malaria species and Plasmodium vivax.

Broad Institute currently conduct a project that compare between Dd2 and HB3 strains of Plasmodium falciparum for better understanding their polymorphism. These 2 strains are the parents of a widely used genetic cross and differ in the frequency of acquisition of drug resistance. Polymorphism in P. falciparum is known to be concentrated in genes that are involved in immune system evasion and pathogenicity. Generating data on polymorphism in P. falciparum can thus not only speed identification of these key loci but also provide important insight into the evolutionary pressures shaping their function. So far the research found that Dd2 strain has a high propensity to acquire drug resistance whereas HB3 does not. Thus, the complete genomic sequences will make it possible to identify the mutations responsible for this important predisposition to acquiring drug resistance.