A new method for estimating species age supports the coexistence of malaria parasites and their Mammalian hosts.
A new method for estimating species age supports the coexistence of malaria parasites and their Mammalian hosts.
复制标题
一种估计物种年龄的新方法支持疟疾寄生虫与其哺乳动物宿主的共存。
DOI：
10.1093/molbev/msv005
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发表时间：
2015
影响因子：
10.7
通讯作者：
Harris,DavidG
中科院分区：
文献类型：
--
作者：
Silva,JoanaC;Egan,Amy;Arze,Cesar;Spouge,JohnL;Harris,DavidG
Species in the genusPlasmodiumcause malaria in humans and infect a variety of mammals and other vertebrates. Currently, estimated ages for several mammalianPlasmodiumparasites differ by as much as one order of magnitude, an inaccuracy that frustrates reliable estimation of evolutionary rates of disease-related traits. We developed a novel statistical approach to dating the relative age of evolutionary lineages, based on Total Least Squares regression. We validated this lineage dating approach by applying it to the genusDrosophila. Using data from theDrosophila12 Genomes project, our approach accurately reconstructs the age of well-establishedDrosophilaclades, including the speciation event that led to the subgeneraDrosophilaand Sophophora, and age of the melanogaster species subgroup. We applied this approach to hundreds of loci from seven mammalianPlasmodiumspecies. We demonstrate the existence of a molecular clock specific to individualPlasmodiumproteins, and estimate the relative age of mammalian-infectingPlasmodium. These analyses indicate that: 1) the split between the human parasitePlasmodium vivaxandP. knowlesi, from Old World monkeys, occurred 6.1 times earlier than that betweenP. falciparumandP. reichenowi, parasites of humans and chimpanzees, respectively; and 2) mammalianPlasmodiumparasites originated 22 times earlier than the split betweenP. falciparumandP. reichenowi. Calibrating the absolute divergence times forPlasmodiumwith eukaryotic substitution rates, we show that the split betweenP. falciparumandP. reichenowioccurred 3.0–5.5 Ma, and that mammalianPlasmodiumparasites originated over 64 Ma. Our results indicate that mammalian-infectingPlasmodiumevolved contemporaneously with their hosts, with little evidence for parasite host-switching on an evolutionary scale, and provide a solid timeframe within which to place the evolution of newPlasmodiumspecies.
