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Massive horizontal gene transfer in bdelloid rotifers
Eugene A Gladyshev1, Matthew Meselson, Irina R Arkhipova
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Science (New York, N.Y.)
|May 31, 2008
Summary
Bdelloid rotifers exhibit extensive horizontal gene transfer, incorporating genes from bacteria, fungi, and plants. These foreign genes, found in telomeric regions, are functional and integrated into the rotifer genome, driving evolutionary innovation.
Area of Science:
- Genomics
- Evolutionary Biology
- Zoology
Background:
- Horizontal gene transfer (HGT) is rare in metazoans, typically linked to symbiosis or parasitism.
- Bdelloid rotifers are a unique group of micro-animals known for their asexual reproduction and resilience.
Purpose of the Study:
- To investigate the extent and origin of foreign genes in bdelloid rotifers.
- To understand the functional integration and evolutionary implications of HGT in this lineage.
Main Methods:
- Bioinformatic analysis of bdelloid genomes to identify genes of non-rotiferan origin.
- Comparative genomics to pinpoint gene locations and identify mobile genetic elements.
- Gene expression analysis and functional assays for selected foreign genes.
Main Results:
- Bdelloid rotifers possess numerous genes acquired from bacteria, fungi, and plants, primarily located in telomeric regions.
- These foreign genes are often associated with mobile genetic elements and vary in integrity, with some being intact and transcribed.
- One bacterial-derived gene was successfully expressed in Escherichia coli, producing an active enzyme, demonstrating functional assimilation.
Conclusions:
- Horizontal gene transfer is a significant factor in bdelloid rotifer evolution, contributing novel genetic material.
- The functional integration of exogenous genes suggests a unique evolutionary mechanism in bdelloids.
- Telomeric regions may serve as hotspots for gene capture and integration in bdelloid genomes.
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