with its relationship with the lemur species in the subgenus vinckeia. other analyses examination of the protease gene (sera) in 18 species has shown that the ancestral state had only a single gene and that gene duplications have occurred in the extant species. this paper confirms the groupings found elsewhere with an asian clade. the rodent species seem to be more closely related to the laverania subgenus than does the subgenus plasmodium. a deletion mutation of ~100 base pairs including part of the ls1 rrna gene is found in the sequences of two african species - p. gonderi and an undescribed parasite taken from a mandrill - and 2 asian species - p. cynomolgi and p. simiovale. this mutation was not found in the other species examined (leucocytozoon caulleryi, leucocytozoon sabrazesi, p. bergei, p. chabaudi, p. falciparum, p. floridense, p. gallacium, p. fragile, p. juxtanucleare, p. knowelsi, p. mexicanum, p. reichenowi, p. relictum, p. simiae, p. vivax, p. yoelii and two unnamed haemoproteus species.) these mutations are rare events and strongly suggests these species are related. another paper suggests that after the mammalian-reptile/bird species split that the subgenus laverina is basal among the mammal species. this study did not include mammalian infecting species other than primate and rodent species and for this reason laverina may not be as basal as the study suggests. the remaining branching order is consistent with other analyses placing the rodent species as the first branch after the p. falciparum/p. reichenowi clade. it places p. malaria and p. ovale as being more closely related to each other than to p. vivax. this is consistent with the proposed asian origin of p. vivax. although bird malaria species use a variety of mosquito vectors from the genera aedes, anopheles, culex, culiseta, mansonia and psorophora, all mammalian species use vectors only from the genus anopheles. this host switch seems to have been associated with a specialization with a particular genus of mosquito. the ability to store haemozoin appears to have evolved only once in the common ancestor of haemoproteus, hepatocystis and plasmodium. a study of the relationships between haemocystis, haemoproteus, leucocytozoon and plasmodium suggests that (1) leucocytozoon is basal (2) haemoproteus is a sister clade to the remainder (3) parahaemoproteus is a sister to plasmodium and (4) haemocystis is nested within plasmodium. as before the bird/lizard species form a distinct clade. in birds the haemoproteus and leucocytozoon species rarely change transmission area. these parasites are restricted to one resident bird fauna over a long evolutionary time span and are not freely spread between the continents with the help of migratory birds. lineages of the genus plasmodium in contrast seem more freely spread between the continents. this suggests that the origin on the genus plasmodium may have coincided with the ability to transfer between avian hosts more easily than the other genera. an analysis of a large number of genera suggested that the taxonomy may need revision. leucocytozoon appears to be basal to most of the haemosporidia. the genera heamoproteus and parahaemaproteus are the next most basal clade. at least one species in the genus heamoproteus grouped with the main plasmodium clade. within the plasmodium clade lay the genera hepatocystis, nycteria and polychromophilus. plasmodium odocoiliei appeared to be very divergent in the clade. within the palsmodium clade the reptile species formed one grouping while the subgenera laverinia, plasmodium and vinkeia also formed subgroupings. these results if confirmed suggest that the taxonomy of the group will need substantial revision. molecular clock estimates all dates estimated so far using a molecular clock should probably be regarded with some suspicion given the existing disagreements between the various authors. the branching order suggested by other analyses concurs with an analysis of the mitochondrial genes this latter paper puts the divergence between the reptile-bird and mammal clades at 38.4 million years ago ± 3.2 million years ago (mya). other divergence times reported include p. falciparum – p. reichenowi - 4 million years ago (±0.9 million years) p. ovale - p. cynomolgi/p. gonderi/p. simiovale/p. fieldi/p. inui/p. fragile/p. coatneyi/p. knowlesi - 19 million years ago p. malariae and p. inui/p. hylobati - 19 million years ago p. malariae/p. inui/p. hylobati - p. chabaudi/p. yoelii - 25.7 million years ago (±2.6 million years) p. knowlesi - p. cynomolgi/p. simiovale/p. fieldi/p. inui/p. fragile/p. coatneyi - 6.3 million years ago (±1.4 million years) an estimate of the dates of evolution of several species using the date of separation of the african species p. gonderi and the asian clade at 10 million years ago gives estimates as follows: p. falciparum - p. reichenowi: 5 million years ago p ovale - p. malariae: 14 million years ago p. inui - p. hylobati: 3 million years ago p. cynomogli - p. simium/p. vivax: 5 million years ago p. fragile - p. cynomogli/p. simium/p. vivax/p. inui/p. hylobati: 6 million years ago p ovale/p. malariae - p. fragile/p. cynomogli/p. simium/p. vivax/p. inui/p. hylobati: 18 million years ago analysis of 45 single copy nuclear genes from eight species (p. berghei, p. chabaudi, p. falciparum, p. gallinaceum, p. knowlesi, p. reichenowi, p. vivax, p. yoelii) using several different phylogenetic methods suggest a divergence date between theileria and plasmodium between 294 million years ago and 314 million years ago. estimates of the mutation rates suggest a date of divergence between p. falciparum and p. reichenowi between 5 million years ago and 7 million years ago. the estimated date of divergence between p. vivax and p. knowlesi was between 15 million years ago and 46 million years ago. this latter period coincides with the radiation of the old world monkeys which these parasites infect. the date of divergences between p. berghei, p. chabaudi and p. yoelii was estimated to be between 34 million years ago and 25 million years ago. the main radiation of the rodent family muridae occurred ~24 million years ago. a paper based on the analysis of 22 nuclear genes suggests a radiation of malarial parasites within the oligocene (34-23 million years ago). another paper examining the dates of evolution using the concatenated sequences of the cytochrome c oxidase iii, cytochrome c oxidase i and cytochrome b genes - all from the mitochondrion - suggested the following dates for the evolution of the species examined (p. coatneyi, p. cynomolgi, p. falciparum, p. fieldi, p. fragile, p. gonderi, p. hylobati, p. inui, p. knowlesi, p. malariae, p. ovale, p. reichenowi, p. simiovale, p. vivax) was as follows: asian-african primate clade divergence: 12 million years ago-19 million years ago primate-rodent clade divergence: 15 million years ago-30 million years ago reptile/bird-mammal clade divergence: 20 million years ago-30 million years ago an estimation of the date of evolution of this genus based upon the mutation rate in the cytochrome b gene places the evolution of p. falciparum at 2.5 million years ago. the authors also estimated that the mammalian species of this genus evolved 12.8 million years ago and that the order haemosporida evolved 16.2 million years ago. while the date of evolution of p. falciparum is consistent with alternative methods, the other two dates are considerably more recent than other published estimates and probably should be treated with caution. another paper which examined primate, rodent, lemur, bird and reptile species suggests that the genus originated between 30 million years ago and 50 million years ago. the split between the reptile/bird and mammalian species occurred between 31.4 million years ago and 47.6 million years ago. the first division in the mammalian species was between laverinia and the others species. the separation of p. falciparum and p. reichenowi was estimated to be between 3.6 million years ago and 7.9 million years ago. the bonobo strains of p. falciparum of were the closest relations to those of humans. this analysis grouped p. ovale with the lemur species and this clade as a sister clade to the rodent species. while this is consistent with the current placement of the lemur species with the rodent species in the subgenus vinckeia, it is inconsistent with the current placement of p. ovale in the subgenus plasmodium. the date of separation of p. ovale from the lemur species was estimated to be 25 million years ago and 35 million years ago and their date of divergence from the rodent species was dated to between 30 million years ago and 50 million years ago. the rodent species first diverged between 10 million years ago and 20 million years ago. p. atherui appears to be more closely related to the p. berghei/p. yoelli clade than to p. chabaudi. p. malariae evolved between 20 million years ago and 30 million years ago and is more closely related to p. vivax than to p. ovale. p vivax and p. cynomogli last shared an ancestor between 2.2 million years ago and 4.5 million years ago. the origin of the asian clade was placed between 5 million years ago and 8.2 million years ago. another estimate of the dates of evolution has proposed that the mammalian plasmodium parasites originated over 64 million years ago and that split between p. falciparum and p. reichenowi occurred 3.0-5.5 million years ago. these authors suggested that the split between p. vivax and p knowlesi occurred 18 million years ago-34 million years ago million years ago. this paper also suggested that the genus plasmodium evolved between 64 million years ago and 120 million years ago. another study has placed the evolution of the subgenus laverina between 3.09 million years ago and 22.93 million years ago. the same paper estimated the p. billbrayi - p.gaboni split between 1.92 million years ago and 4.69 million years ago and the p. reichenowi - p. falciparum between 4.02 million years ago and 7.84 million years ago. bats evolved between 51.5 million years ago and 75.3 million years ago. since it appears that the mammalian infecting plasmodium species evolved from a bat infecting species, this estimate may provide an upper limit for the date of evolution of these species of plasmodium. a larger study suggests that bats evolved 58.9 million years ago. this upper limit for the date of bat infecting parasites is consistent with the estimates of the dates of evolution of the mammalian infecting plasmodium species. the divergence of old world monkeys and apes has been dated to 25 million years ago to 30 million years ago. since the subgenus laverinia infects apes rather than monkeys, this date suggests an upper limit for the evolution of this subgenus. this date also places an upper limit on the date when the species infecting old world monkeys evolved. a bayesian estimate has suggested that the genus plasmodium evolved about 35 million years ago. the authors also found that the lemur clade evolved about 20 million years ago, the rodent species about 12 million years ago, the two known ovale species about 25 million years ago and the asian species about 8 million years ago. the subgenus laverinia evolved about 18 million years ago. the branching order in this subgenus suggests that p. billbrayi and p. gaboni are sister species and form an early diverging clade. p. falciparum and p. reichenowi are sister species and they are related to p. billcolinsi. a bayesian estimate of the date of the most recent common ancestor of the rodent species put this between 4.5 million years ago and 17.9 million years ago. an estimate based on the genome sequences of plasmodium gallinaceum and plasmodium relictum and the previously sequenced mammalian parasite genomes has suggested a divergence date of 10 million years ago. this estimate was based on a separation date of 1 million years for the two ovale species. the dates seem to be at odds with other estimates. this may be because the date of separation of the ovale species currently has considerable variance: the 95% confidence interval in one paper was 0.5 – 7.7 mya. laverania four species (p. billbrayi, p. billcollinsi, p. falciparum and p. reichenowi) form a clade within the subgenus lavernia. this subgenus is more closely related to the other primate species than to the bird species or the included leuocytozoon species. both p. billbrayi and p. billcollinsi infect both the chimpanzee subspecies included in this study (pan troglodytes troglodytes and pan troglodytes schweinfurthii). p. falciparum infects the bonobo (pan paniscus) and p. reichenowi infects only one subspecies (pan troglodytes