The molecular karyotypes of the African murine malaria parasites P. be
rghei (3 strains, 2 lines) P. yoelii (2 strains) P. chabaudi (3 strain
s, 1 line) and P. vinckei (4 strains) have been studied using orthogon
al field alternation gel electrophoresis (OFAGE). The genome of each s
pecies was resolved into 9 to 11 distinct chromosomal DNA bands molecu
les of varying intensities which seem to represent 14 chromosomes rang
ing in size from 600 kb to 3 500 kb. The position of certain chromosom
es allowed the identification of a unique karyotype for each of the st
rains and lines under study. P. yoelii appears by criteria of chromoso
me size, chromosome numbers and localisation of DNA probes to differ c
onsiderably from the other three rodent malaria species. The chromosom
al location of 5 DNA probes allowed the identification of correspondin
g chromosomes in rodent malaria parasites and the differentiation betw
een species and strains. Assignment of the ''PMMSA'' gene of P. c. cha
baudi IP-PC1 enables the distinction of the four rodent malaria specie
s. The molecular karyotype combined to chromosomal assignment of DNA p
robes provides a useful tool for a more precise characterization by a
genetic definition of malaria parasites.