- Top of page
- Life of ciliates
- Programmed genome rearrangement in Tetrahymena
- DNA elimination in Tetrahymena is epigenetically regulated
- An RNAi-related mechanism is required for DNA elimination
- DNA elimination is regulated by scnRNAs
- Potential roles of DNA elimination and IESs
- Are DNA eliminations in other eukaryotes regulated by small RNAs?
Developmentally programmed genome rearrangement has been observed in a variety of eukaryotes from vertebrates to worms to protists, and it provides an interesting exception to the general rule of the constancy of the genome. DNA elimination in the ciliated protozoan Tetrahymena is one of the most well-characterized programmed genome rearrangement events. DNA elimination in the newly formed macronucleus of Tetrahymena is epigenetically regulated by the DNA sequence of the parental macronucleus. Dicer-produced, Piwi-associated small RNAs mediate this epigenetic regulation, probably through a whole-genome comparison of the germline micronucleus to the somatic macronucleus. However, a correlation between small RNAs and programmed genome rearrangement could not be detected in the worm Ascaris suum. Therefore, different types of eukaryotes may have developed unique solutions to perform genome rearrangement.