Recent transcontinental sweep of Toxoplasma gondii driven by a single monomorphic chromosome (original) (raw)
Related papers
Genetic diversity of Toxoplasma gondii in animals and humans
Philosophical Transactions of the Royal Society B: Biological Sciences, 2009
Toxoplasma gondii is one of the most widespread parasites of domestic, wild, and companion animals, and it also commonly infects humans. Toxoplasma gondii has a complex life cycle. Sexual development occurs only in the cat gut, while asexual replication occurs in many vertebrate hosts. These features combine to create an unusual population structure. The vast majority of strains in North America and Europe fall into three recently derived, clonal lineages known as types I, II and III. Recent studies have revealed that South American strains are more genetically diverse and comprise distinct genotypes. These differences have been shaped by infrequent sexual recombination, population sweeps and biogeography. The majority of human infections that have been studied in North America and Europe are caused by type II strains, which are also common in agricultural animals from these regions. In contrast, several diverse genotypes of T. gondii are associated with severe infections in humans ...
Infection Genetics and Evolution
Recent population studies revealed that a few major clonal lineages of Toxoplasma gondii dominate in different geographical regions. The Type II and III lineages are widespread in all continents and dominate in Europe, Africa and North America. In addition, the type 12 lineage is the most common type in wildlife in North America, the Africa 1 and 3 are among the major types in Africa, and ToxoDB PCR-RFLP #9 is the major type in China. Overall the T. gondii strains are more diverse in South America than any other regions. Here, we analyzed 164 T. gondii isolates from three countries in Central America (Guatemala, Nicaragua, Costa Rica), from one country in Caribbean (Grenada) and five countries from South America (Venezuela, Colombia, Peru, Chile, and Argentina). The multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based genotyping of 11 polymorphic markers (SAG1, SAG2, alt.SAG2, SAG3, BTUB, GRA6, L358, PK1, C22-8, C29-2 and Apico) were applied to 148 free-range chicken (Gallus domesticus) isolates and 16 isolates from domestic cats (Felis catus) in Colombia; 42 genotypes were identified. Linkage disequilibrium analysis indicated more frequent genetic recombination in populations of Nicaragua and Colombia, and to a lesser degree in populations of Costa Rica and Argentina. Bayesian structural analysis identified at least three genetic clusters, and phylogenetic network analysis identified four major groups. The ToxoDB PCR-RFLP #7, Type III and II were major lineages identified from Central and South America, with high frequencies of the closely related ToxoDB PCR-RFLP #7 and Type III lineages. Taken together, this study revealed high diversity within and between T. gondii populations in Central and South America, and the dominance of Type III and its closely related ToxoDB PCR-RFLP #7 lineages. Fig. 2. Pairwise Fst of 10 sample populations and three reference populations. Comparison of populations were conducted using Arlequin ver 3.5. The heat map indicates the Fst value.
International Journal for Parasitology, 2011
Toxoplasma gondii is a widespread parasite of animals that causes zoonotic infections in humans. Previous studies have revealed a strongly clonal population structure in North America and Europe, while strains from South America are genetically separate and more diverse. However, the composition within North America has been questioned by recent descriptions of genetically more variable strains from this region. Here, we examined an expanded set of isolates using sequenced-based phylogenetic and population analyses to re-evaluate the population structure of T. gondii in North America. Our findings reveal that isolates previously defined by atypical restriction fragment length polymorphism patterns fall into two discrete groups. In one case, these new isolates represent variants of an existing lineage, from which they differ only by minor mutational drift. However, in the second case, it is evident that these isolates define a completely new lineage that is common in North America. Support for this new lineage was based on phylogeny, principle components analysis, STRUCTURE analyses, and statistical analysis of gene flow between groups. This new group, referred to as haplogroup 12, contains divergent genotypes previously referred to as A and X, isolated from sea otters. Consistent with this, group 12 was found primarily in wild animals, as well as occasionally in humans. This new lineage also has a highly clonal population structure. Analysis of the inheritance of multilocus genotypes revealed that different strains within group 12 are the products of a single recombination event between type 2 and a unique parental lineage. Collectively, the archetypal type 2 has been associated with clonal expansion of a small number of lineages in the North, as a consequence of separate but infrequent genetic crosses with several different parental lines.
PLoS Neglected Tropical Diseases, 2014
Background: Previous studies have stressed the genetic divergence and high pathogenicity of strains of T. gondii from French Guiana. Although strains from coastal, human adapted environments (so called anthropized) resemble those found in other regions of the Caribbean, strains collected from inland jungle environment are genetically quite diverse. To better understand the composition of these distinct strain types, we undertook a more in depth analysis of T. gondii strains from French Guiana including profiling of chromosome 1a (Chr1a), which is often shared as a single monomorphic haplotype among lineages that are otherwise genetically distinct. Methodology/Principal Findings: Comparison of intron sequences from selectively neutral genes indicated that anthropized strains were most closely related to clonal type III strains from North America, although wider RFLP analysis revealed that they are natural hybrids. In contrast, strains isolated from the jungle were genetically very diverse. Remarkably, nearly all anthropized strains contained the monomorphic version of Chr1a while wild stains were extremely divergent. The presence of the monomorphic Chr1a strongly correlated with greater transmission in domestic cats, although there were several exceptions, indicating that other factors also contribute. Anthropized strains also varied in their virulence in laboratory mice, and this pattern could not be explained by the simple combination of previously identified virulence factors, indicating that other genetic determinants influence pathogenicity. Conclusions/Significance: Our studies underscore the marked genetic separation of anthropized and wild strains of T. gondii in French Guiana and provide additional evidence that the presence of Chr1a is associated with successful expansion of widely different lineages within diverse geographic areas. The predominance of Chr1a among strains in the anthropized environment suggests that it may confer an advantage for transmission in this environment, and thus potentially contribute to the spread of pathogenecity determinants.
mBio, 2011
Toxoplasma gondii is a common parasite of animals that also causes a zoonotic infection in humans. Previous studies have revealed a strongly clonal population structure that is shared between North America and Europe, while South American strains show greater genetic diversity and evidence of sexual recombination. The common inheritance of a monomorphic version of chromosome Ia (referred to as ChrIa*) among three clonal lineages from North America and Europe suggests that inheritance of this chromosome might underlie their recent clonal expansion. To further examine the diversity and distribution of ChrIa, we have analyzed additional strains with greater geographic diversity. Our findings reveal that the same haplotype of ChrIa* is found in the clonal lineages from North America and Europe and in older lineages in South America, where sexual recombination is more common. Although lineages from all three continents harbor the same conserved ChrIa* haplotype, strains from North Americ...
Phylogeography of Toxoplasma gondii points to a South American origin
Infection, Genetics and Evolution, 2017
Toxoplasma gondii, a protozoan found ubiquitously in mammals and birds, is the etiologic agent of toxoplasmosis, a disease causing substantial Public Health burden worldwide, including about 200,000 new cases of congenital toxoplasmosis each year. Clinical severity has been shown to vary across geographical regions, with South America exhibiting the highest burden. Unfortunately, the drivers of these heterogeneities are still poorly understood, and the geographical origin and historical spread of the pathogen worldwide are currently uncertain. A worldwide sample of 168 T. gondii isolates gathered in 13 populations was sequenced for five fragments of genes (140 single nucleotide polymorphisms from 3,153 bp per isolate). Phylogeny based on Maximum likelihood methods with estimation of the time to the most recent common ancestor (TMRCA) and geostatistical analyses were performed for inferring the putative origin of T. gondii. We show that extant strains of the pathogen likely evolved from a South American ancestor, around 1.5 million years ago, and reconstruct the subsequent spread of the pathogen worldwide. This emergence is much more recent than the appearance of ancestral T. gondii, believed to have taken place about 11 My ago, and follows the arrival of felids in this part of the world. We posit that an ancestral lineage of T. gondii likely arrived in South America with felids and that the evolution of oral infectivity through carnivorism and the radiation of felids in this region enabled a new strain to outcompete the ancestral lineage and undergo a pandemic radiation.
PLOS Neglected Tropical Diseases, 2019
Toxoplasma gondii is a zoonotic protozoan with a worldwide distribution and which can infects virtually all warm-blooded species, including human. Clinical expression of human toxoplasmosis, as well as T. gondii strains diversity, exhibit contrasting patterns across geographic regions. The determinants of this geographical structure are poorly understood, but a growing body of evidence supports an important role of human-mediated migrations of T. gondii hosts in the intercontinental dissemination of some parasite lineages. The results of our study conducted in Senegal suggest that the invasive house mouse-which was introduced in the port cities of this country through maritime trade since colonial times-has a dramatic influence on the T. gondii populations of invaded areas. This important T. gondii reservoir seems to be a vector for the intercontinental migrations of T. gondii. In addition, it may have a role in the selection (or the counterselection) of local T. gondii populations found in invaded areas. This study provides insights into the mechanisms shaping T. gondii populations, thereby determining which strains will be available for human and animal infection.
Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases
Recent population studies revealed that a few major clonal lineages of Toxoplasma gondii dominate in different geographical regions. The Type II and III lineages are widespread in all continents and dominate in Europe, Africa and North America. In addition, the type 12 lineage is the most common type in wildlife in North America, the Africa 1 and 3 are among the major types in Africa, and ToxoDB PCR-RFLP #9 is the major type in China. Overall the T. gondii strains are more diverse in South America than any other regions. Here, we analyzed 164 T. gondii isolates from three countries in Central America (Guatemala, Nicaragua, Costa Rica), from one country in Caribbean (Grenada) and five countries from South America (Venezuela, Colombia, Peru, Chile, and Argentina). The multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based genotyping of 11 polymorphic markers (SAG1, SAG2, alt.SAG2, SAG3, BTUB, GRA6, L358, PK1, C22-8, C29-2 and Apico) were applie...
International Journal for Parasitology, 2009
The cosmopolitan parasitic pathogen Toxoplasma gondii is capable of infecting essentially any warmblooded vertebrate worldwide, including most birds and mammals, and establishes chronic infections in one-third of the globe's human population. The success of this highly prevalent zoonosis is largely the result of its ability to propagate both sexually and clonally. Frequent genetic exchanges via sexual recombination among extant parasite lineages that mix in the definitive felid host produces new lines that emerge to expand the parasite's host range and cause outbreaks. Highly successful lines spread clonally via carnivorism and in some cases sweep to pandemic levels. The extent to which sexual reproduction versus clonal expansion shapes Toxoplasma's current, global population genetic structure is the central question this review will attempt to answer.