Population Genetics Provides Evidence for Recombination in Giardia

  title={Population Genetics Provides Evidence for Recombination in Giardia},
  author={Margarethe A. Cooper and Rodney D. Adam and Michael Worobey and Charles R. Sterling},
  journal={Current Biology},

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Genetic Exchange Within and Between Assemblages of Giardia duodenalis
Molecular signatures consistent with meiotic sex or genetic exchange are detected, including low levels of heterozygosity, as indicated by allelic sequence divergence within isolates, and intra‐ and inter‐assemblage recombination.
Nuclear inheritance and genetic exchange in Giardia intestinalis, a divergent eukaryote with two nuclei
This dissertation describes the development of morpholinos as a new tool for gene knockdown in Giardia and demonstrates that nuclear fusion and genetic exchange occur between nuclei in the cyst, a process the authors have termed diplomixis.
Development of a Multilocus Sequence Typing Scheme for Giardia intestinalis
To evaluate new markers for the study of the diversity and intra-taxa genetic structure of G. intestinalis in silico and in DNA obtained from stool samples, nine constitutive genes in 80 complete genome sequences and in a group of 24 stool samples from Colombia were analysed.
Zoonotic potential of Giardia.
Multilocus genotyping of Giardia duodenalis reveals striking differences between assemblages A and B.
Population-based analyses of Giardia duodenalis is consistent with the clonal assemblage structure
The analyses indicate that recombination between isolates from different assemblages are apparently very rare or absent in the natural population of Giardia duodenalis.
Molecular epidemiology of giardiasis.
Genome analysis and comparative genomics of a Giardia intestinalis assemblage E isolate
Compared genomics of the three diverse Giardia intestinalis isolates P15, GS and WB to define a core proteome for this species complex and to identify lineage-specific genes were used to identify novel members of the VSP, NEK Kinase and HCMP gene families.
Genome-wide analyses of recombination suggest that Giardia intestinalis assemblages represent different species.
The authors' results indicate very low frequency of recombination between the syntenic core genes, suggesting that G. intestinalis assemblages are genetically isolated lineages and thus should be viewed as separated Giardia species.


Biology of Giardia lamblia
  • R. D. Adam
  • Biology
    Clinical Microbiology Reviews
  • 2001
The Giardia genome project promises to greatly increase the understanding of this interesting and enigmatic organism.
Unusually Low Levels of Genetic Variation among Giardia lamblia Isolates
It is proposed that the distinct patterns of genetic-variation distribution among lineages are a consequence of the presence of genetic exchange, and these findings have implications for the regulation of gene expression, as well as the mode of reproduction in the parasite.
Genomic Minimalism in the Early Diverging Intestinal Parasite Giardia lamblia
The genome of the eukaryotic protist Giardia lamblia, an important human intestinal parasite, is compact in structure and content, contains few introns or mitochondrial relics, and has simplified
Genetic characterization of isolates of Giardia duodenalis by enzyme electrophoresis: implications for reproductive biology, population structure, taxonomy, and epidemiology.
Data suggest that clonal lineages within G. duodenalis are evolutionarily independent, and there was a significant overall correlation between genetic distance separating zymodemes and occurrence in different host species, interpreted as evidence for zoonotic transmission of the parasite.
A clonal theory of parasitic protozoa: the population structures of Entamoeba, Giardia, Leishmania, Naegleria, Plasmodium, Trichomonas, and Trypanosoma and their medical and taxonomical consequences.
A population genetic analysis of extensive data on biochemical polymorphisms indicates that the two fundamental consequences of sexual reproduction are apparently rare or absent in natural populations of the parasitic protozoa.
Genome ploidy in different stages of the Giardia lamblia life cycle
The nuclear and cellular genome ploidy of G. lamblia cells during all stages of the life cycle is determined and it is suggested that the newly excysted cell, for which the term ‘excyzoite’ is suggested, contains four nuclei.
The Giardia lamblia trophozoite contains sets of closely related chromosomes.
Densitometric comparisons of chromosome bands from known numbers of Plasmodium falciparum ring stage forms andknown numbers of Giardia trophozoites suggest that minor bands MBa and MBb are present in each Giardian trophozite.
Evidence for clonal propagation in natural isolates of Plasmodium falciparum from Venezuela
The hypothesis that the population structure of P. falciparum in Venezuela, but not in Africa, is predominantly clonal is supported and three RAPD characters that could be useful as “tags” for rapid species identification are identified.
The molecular epidemiology of Giardia lamblia: a sequence-based approach.
To develop a sequence-based classification system, the gene encoding the metabolic enzyme triose phosphate isomerase (tim) was sequenced from a number of G. lamblia isolates of various host origins and restriction enzymes were identified that can distinguish among isolates without the need for sequencing.