Transposons are ubiquitous genetic elements with the ability to move around in their hosts’ genomes. This mobility can induce mutations and therefore transposons most probably play an important role in creating genetic diversity in their hosts . But nevertheless transposons can have ditrimentrial effect on their hosts’ genomes: insertions into new genomic locations can also lead to gene disruption. The repetitive nature of transposons can enhance ectopic recombination followed by the removal of functional genes or exons . Hence the evolution of genome defence mechanisms against transposable elements is not surprising. A mechanism exclusively found in filamentous fungi is the repeat induced point mutation (RIP). This mechanism acts premeiotical and induces C:G to T:A transitions in both copies of a duplicated sequence . Here we present an investigation for RIP in multiple copies of the Aspergillus niger retrotransposon AniTa1 and the Penicillium chrysogenum class II transposon PeTra2. RIP was identified in both elements, representing the first observation of RIP in these two fungi. For PeTra2 all sequences investigated seem to be effected by a moderate type of RIP in a varying extend. AniTa1 copies seem to be unRIPed with the exception of two copies in which 20% of all nucleotides have been altered due to RIP. These findings suggest a rather selective but very strong type of RIP in A. niger.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)