Send to

Choose Destination
See comment in PubMed Commons below
J Eukaryot Microbiol. 2009 Nov-Dec;56(6):504-18. doi: 10.1111/j.1550-7408.2009.00443.x.

Genetic exchange within and between assemblages of Giardia duodenalis.

Author information

Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA.

Erratum in

  • J Eukaryot Microbiol. 2010 Jan 1;57(1):94.


Meiotic sex evolved early in the history of eukaryotes. Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis), a parasitic protist belonging to an early diverging lineage of eukaryotes, shows no cytological or physiological evidence of meiotic or sexual processes. Recent molecular analyses challenge the idea that G. duodenalis is a strictly clonal organism by providing evidence of recombination between homologous chromosomes within one subgroup (Assemblage A) of this species as well as genetic transfer from one subgroup to another (Assemblage A-B). Because recombination is not well documented and because it is not known whether the observed inter-assemblage transfer represents true reciprocal genetic exchange or a non-sexual process, we analyzed genic sequences from all major subgroups (Assemblages A-G) of this species. For all assemblages, we detected molecular signatures consistent with meiotic sex or genetic exchange, including low levels of heterozygosity, as indicated by allelic sequence divergence within isolates, and intra- and inter-assemblage recombination. The identification of recombination between assemblages suggests a shared gene pool and calls into question whether it is appropriate to divide the genetically distinct assemblages of G. duodenalis into a species complex.

[Indexed for MEDLINE]

Publication types, MeSH terms, Substance, Secondary source ID, Grant support

Publication types

MeSH terms


Secondary source ID

Grant support

PubMed Commons home

PubMed Commons


    Supplemental Content

    Full text links

    Icon for Wiley
    Loading ...
    Support Center