Biochemical Diversification through Foreign Gene Expression in Bdelloid Rotifers

• DOI: 10.1371/journal.pgen.1003035
• Publication Date: 2012-11-15T21:52:50Z
• Authors: Chiara Boschetti; Adrian Carr; Alastair Crisp; Isobel Eyres; Yuan Wang-Koh; Esther Lubzens; Timothy G. Barrac...; Gos Micklem; Alan Tunnacliffe
• Keywords: Horizontal Gene Transfer; Cryptobiosis

Bdelloid rotifers are microinvertebrates with unique characteristics: they have survived tens of millions years without sexual reproduction; withstand extreme desiccation by undergoing anhydrobiosis; and tolerate very high levels ionizing radiation. Recent evidence suggests that subtelomeric regions the bdelloid genome contain sequences originating from other organisms horizontal gene transfer (HGT), which some known to be transcribed. However, extent foreign expression plays a role in physiology is unknown. We address this first large scale analysis transcriptome Adineta ricciae: cDNA libraries hydrated desiccated bdelloids were subjected massively parallel sequencing assembled transcripts compared against UniProtKB database blastx identify their putative products. Of ∼29,000 matched transcripts, ∼10% inferred matches horizontally acquired, mainly eubacteria but also fungi, protists, algae. After allowing for possible sources error, rate HGT at least 8%–9%, level significantly higher than invertebrates. verified nature phylogenetic demonstrating linkage genes metazoan genome. Approximately 80% acquired expressed code enzymes, these represent 39% enzymes identified pathways. Many encoded enhance biochemistry metazoans, example, potentiating toxin degradation or generation antioxidants key metabolites. They supplement, occasionally potentially replace, existing functions. therefore express on unprecedented animals, make profound contribution metabolism. This represents potential mechanism ancient asexuals adapt rapidly changing environments thereby persist over long evolutionary time periods absence sex.