1. Academic Validation
  2. The complete sequence of the smallest known nuclear genome from the microsporidian Encephalitozoon intestinalis

The complete sequence of the smallest known nuclear genome from the microsporidian Encephalitozoon intestinalis

  • Nat Commun. 2010 Sep 21;1:77. doi: 10.1038/ncomms1082.
Nicolas Corradi 1 Jean-François Pombert Laurent Farinelli Elizabeth S Didier Patrick J Keeling
Affiliations

Affiliation

  • 1 Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, 3529-6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4.
Abstract

The genome of the microsporidia Encephalitozoon cuniculi is widely recognized as a model for extreme reduction and compaction. At only 2.9 Mbp, the genome encodes approximately 2,000 densely packed genes and little else. However, the nuclear genome of its sister, Encephalitozoon intestinalis, is even more reduced; at 2.3 Mbp, it represents a 20% reduction from an already severely compacted genome, raising the question, what else can be lost? In this paper, we describe the complete sequence of the E. intestinalis genome and its comparison with that of E. cuniculi. The two species share a conserved gene content, order and density over most of their genomes. The exceptions are the subtelomeric regions, where E. intestinalis chromosomes are missing large gene blocks of sequence found in E. cuniculi. In the remaining gene-dense chromosome 'cores', the diminutive intergenic sequences and introns are actually more highly conserved than the genes themselves, suggesting that they have reached the limits of reduction for a fully functional genome.

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