Horizontal gene transfer in chromalveolates.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Nosenko
Tetyana
T
University of Iowa, Department of Biological Sciences and the Roy J, Carver Center for Comparative Genomics, 446 Biology Building, Iowa City, Iowa 52242, USA. tetyana-nosenko@uiowa.edu
Bhattacharya
Debashish
D
D000818:Animals; D002460:Cell Line; D004141:Dinoflagellida / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D004734:Energy Metabolism; D020224:Expressed Sequence Tags; D022761:Gene Transfer, Horizontal; D018503:Genome, Protozoan; D007527:Isoenzymes / Q000235:genetics; D050506:Mutant Chimeric Proteins / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D015800:Protozoan Proteins / Q000235:genetics*; D000637:Transaminases / Q000235:genetics
D007527:Isoenzymes; D050506:Mutant Chimeric Proteins; D015800:Protozoan Proteins; D010088:Oxidoreductases; D000637:Transaminases