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Selfish DNA: homing endonucleases find a home
1Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada. rwb@st-andrews.ac.uk
Current Biology : CB
|February 13, 2009
Summary
Self-splicing group I introns, with or without homing endonucleases, may evolve into mobile genetic elements. Their shared targeting of conserved DNA sequences could drive this evolutionary process.
Area of Science:
- Molecular Biology
- Genetics
- Evolutionary Biology
Background:
- Self-splicing group I introns are genetic elements that can excise themselves from RNA molecules.
- These introns exist in two forms: those with an associated homing endonuclease and those without.
- Homing endonucleases are enzymes that facilitate the mobility of genetic elements, including introns.
Purpose of the Study:
- To investigate the association between self-splicing introns and homing endonucleases.
- To understand the evolution of composite selfish genetic elements formed by introns and endonucleases.
- To explore the role of conserved sequence targeting in the evolution of mobile genetic elements.
Main Methods:
- Comparative analysis of intron and endonuclease sequences.
- Bioinformatic identification of conserved target sequences.
- Phylogenetic analysis of intron-exonuclease associations.
Main Results:
- A shared characteristic between self-splicing introns and homing endonucleases is their ability to target specific, conserved DNA sequences.
- This conserved sequence targeting mechanism is proposed as a key factor driving the co-evolution of introns and endonucleases.
- The association of endonucleases with introns enhances intron mobility and propagation.
Conclusions:
- The targeting of conserved sequences provides a molecular basis for the association between self-splicing introns and homing endonucleases.
- This shared targeting mechanism is a likely driver for the formation of composite mobile genetic elements.
- Understanding this association sheds light on the evolution of selfish genetic elements.
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