Article

Horizontal gene transfer in chromalveolates. BMC Evol Biol 7(1):173

University of Iowa, Department of Biological Sciences and the Roy J, Carver Center for Comparative Genomics, 446 Biology Building, Iowa City, Iowa 52242, USA.
BMC Evolutionary Biology (Impact Factor: 3.41). 02/2007; 7:173. DOI: 10.1186/1471-2148-7-173
Source: PubMed

ABSTRACT Horizontal gene transfer (HGT), the non-genealogical transfer of genetic material between different organisms, is considered a potentially important mechanism of genome evolution in eukaryotes. Using phylogenomic analyses of expressed sequence tag (EST) data generated from a clonal cell line of a free living dinoflagellate alga Karenia brevis, we investigated the impact of HGT on genome evolution in unicellular chromalveolate protists.
We identified 16 proteins that have originated in chromalveolates through ancient HGTs before the divergence of the genera Karenia and Karlodinium and one protein that was derived through a more recent HGT. Detailed analysis of the phylogeny and distribution of identified proteins demonstrates that eight have resulted from independent HGTs in several eukaryotic lineages.
Recurring intra- and interdomain gene exchange provides an important source of genetic novelty not only in parasitic taxa as previously demonstrated but as we show here, also in free-living protists. Investigating the tempo and mode of evolution of horizontally transferred genes in protists will therefore advance our understanding of mechanisms of adaptation in eukaryotes.

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    • "Given this current state of understanding, the nuclear genomes of peridinin dinoflagellates are expected to show a history of EGT involving at least the canonical red algal endosymbiosis (Li et al. 2006), although other cryptic endosymbiosis are also likely to have occurred during the long evolutionary history of dinoflagellates and sister phyla such as stramenopiles (Moustafa et al. 2009, Baurain et al. 2010) that stretches back hundreds of millions of years (Yoon et al. 2004). In addition, HGT between dinoflagellates and various bacterial sources has been demonstrated in recent studies (Nosenko and Bhattacharya 2007, Keeling 2009). Intriguingly, this complex history of gene recruitment in dinoflagellates occurs in the backdrop of some of the most peculiar properties known with respect to cell and DNA biology (Wisecaver and Hackett 2011): e.g., permanently condensed chromosomes, highly reduced and fragmented organelle DNA (Koumandou et al. 2004), and nuclear genomes of immense size, i.e., estimate ranging from 1.5 to 220 Gbp (LaJeunesse et al. 2005, Hackett and Bhattacharya 2008). "
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    • "In fact, analyses of the genomes and proteomes of model eukaryotes have in some cases suggested that lateral gene transfer, especially between endosymbionts and host lineages may be extensive (e.g. Nosenko and Bhattacharya, 2007; Moustafa et al. 2009; Worden et al. 2009). This is particularly problematic when considering parasites and nascent endosymbiont lineages, where gene transfer events may blur the boundaries between host and symbiont genomes, as in the apicomplexans and the well studied arthropod parasite Wolbachia (Huang et al. 2004; Dunning Hotopp et al. 2007). "
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