Transposable element insertions have been linked to many diseases including hemophilia, severe combined immunodeficiency, and predisposition to cancer.
Studies in Drosophila, Arabidopsis thaliana, and mice all indicate that small interfering RNAs are responsible for transposon silencing.
piRNAs could, however, act on multiple levels, including guiding heterochromatin assembly and possibly playing a role in translation as well .
[3] In 2003, piRNAs derived largely from repeated sequence elements, including transposons, were found in abundance in male and female Drosophila germlines.
In 2006, a study by Margaret Roth Woodhouse, Michael Freeling, and Damon Lisch identified a gene that inhibits the transcription of both transposons and paramuted color gens in maize.
[5] The gene, called Mediator of paramutation1 (Mop1), codes for an RNA-processing enzyme that is necessary for making the small RNAs that are responsible for silencing the transposon MuDR.
[3] The flies thus developed a maternally inherited technique for combating the invasive DNA and silencing the transposons, now known as P cytotype.