Population structure of Toxoplasma gondii: clonal expansion driven by infrequent recombination and selective sweeps.
Toxoplasma gondii is among the most successful parasites. It is capable of infecting all warm-blooded animals and causing opportunistic disease in humans. T. gondii has a striking clonal population structure consisting of three predominant lineages in North America and Europe. Clonality is associated with the recent emergence of a monomorphic version of Chr1a, which drove a selective genetic sweep within the past 10,000 years. Strains from South America diverged from those in North America some 1-2 mya; recently, however, the monomorphic Chr1a has extended into regions of South America, where it is also associated with clonality. The recent spread of a few dominant lineages has dramatically shaped the population structure of T. gondii and has resulted in most lineages sharing a highly pathogenic nature. Understanding the factors that have shaped the population structure of T. gondii has implications for the emergence and transmission of human pathogens.
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, 63130, USA. sibley@wustl.edu
L David
LD
Sibley
James W
JW
Ajioka
D000818:Animals; D017125:Genes, Protozoan; D006801:Humans; D009656:North America; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic; D012641:Selection, Genetic; D013020:South America; D014122:Toxoplasma / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D014123:Toxoplasmosis / Q000469:parasitology / Q000635:transmission; D014774:Virulence / Q000235:genetics