Early Origin and Recent Expansion of Plasmodium falciparum

Abstract

The emergence of virulent Plasmodium falciparum in Africa within the past 6000 years as a result of a cascade of changes in human behavior and mosquito transmission has recently been hypothesized. Here, we provide genetic evidence for a sudden increase in the African malaria parasite population about 10,000 years ago, followed by migration to other regions on the basis of variation in 100 worldwide mitochondrial DNA sequences. However, both the world and some regional populations appear to be older (50,000 to 100,000 years old), suggesting an earlier wave of migration out of Africa, perhaps during the Pleistocene migration of human beings.

Haplotype Trees and Modern Human Origins

“…The log-likelihood ratio test of homogeneity of the malarial out-of-Africa range expansion with the pooled human data for the most recent out-of-Africa range expansion yields a chi-square value of 1.97 (P-value of 0.16) for the 42,000-year date, and 2.54 (P-value of 0.11) for the 35,000-year date. Hence, the data of Joy et al (2003) are compatible with the hypothesis that the malarial parasite spread outof-Africa with their human hosts in the most recent out-ofAfrica range expansion shown in Figure 9. However, the 95% confidence interval for the malarial expansion out-ofAfrica is 113,000-5,900 years ago for the older calibration, and 93,700-4,900 years ago for the younger calibration.…”

“…There has been speculation that this parasite could have moved out of Africa along with the most recent out-of-Africa expansion event of its human hosts, or alternatively it spread much more recently due to changes associated with the emergence of agriculture (Volkman et al, 2001;Joy et al, 2003). To address these issues, mtDNA sequence variation was recently surveyed in 100 worldwide isolates of the malarial parasite (Joy et al, 2003), and Templeton (2004a) performed a nested-clade phylogeographic analysis of these data. Isolation by distance dominates the most recent evolution of P. faciparum in this analysis, but there is also a significant range expansion, most likely out of Africa, that dates to 35,000 or 42,000 years ago, depending on the calibration date used.…”

Molecular population genetics of SLC4A1 and Southeast Asian Ovalocytosis

“…This could have happened due to simple genetic drift during the spread of Austronesian speakers. Alternatively, it is most likely that P. falciparum was present in many of the regions into which the Austronesian expansion occurred, 32 meaning that malaria-related positive natural selection may be responsible for recent increases in SAO frequency. A second scenario that could explain the lack of SAOlike chromosomes in Taiwan is that SAO has its origins in a different geographic area.…”

Morphological versus molecular identification of avian Haemosporidia: an exploration of three species concepts

“…The nature of genetic variation within species of haemosporidian parasites has not been well explored. Joy et al (2003) found 6 bases differing in the cytochrome b gene of P. falciparum of humans, but these samples were taken over a wide geographical range. Variation in the cytochrome b gene is typically observed for avian haemosporidian parasites even at local sites as described here (Bensch et al 2000 ;Ricklefs and Fallon, 2002 ;Waldenstrom et al 2002 ;Fallon et al 2003 a, b;Schrenzel et al 2003 ;Beadell et al 2004 ;Bensch et al 2004 ;Fallon et al 2005 ;Ricklefs et al 2005).…”