The genome of the choanoflagellate Monosiga brevicollis and the origin of metazoans

Department of Molecular and Cell Biology and the Center for Integrative Genomics, University of California, Berkeley, California 94720, USA.
Nature (Impact Factor: 42.35). 02/2008; 451(7180):783-788. DOI: 10.1038/nature06617

ABSTRACT Choanoflagellates are the closest known relatives of metazoans. To discover potential molecular mechanisms underlying the evolution of metazoan multicellularity, we sequenced and analysed the genome of the unicellular choanoflagellate Monosiga brevicollis. The genome contains approximately 9,200 intron-rich genes, including a number that encode cell adhesion and signalling protein domains that are otherwise restricted to metazoans. Here we show that the physical linkages among protein domains often differ between M. brevicollis and metazoans, suggesting that abundant domain shuffling followed the separation of the choanoflagellate and metazoan lineages. The completion of the M. brevicollis genome allows us to reconstruct with increasing resolution the genomic changes that accompanied the origin of metazoans.

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