Plant Retrotransposons

Retrotransposons are mobile genetic elements that transpose through reverse transcription of an RNA intermediate. Retrotransposons are ubiquitous in plants and play a major role in plant gene and genome evolution. In the maize 50-80 % and in the wheat 90 % of the genome made up retrotransposons.It is believed that retrotransposons originated at the beginning of the transition from a putative RNA-based cellular genome to the DNA-based genome. The ubiquity of plant retrotransposons and their extreme sequence heterogeneity suggests that they were present in the first plants. Alternatively, retrotransposons may have originated after the creation of the first eukaryotes, and have reached their current wide dispersal by a combination of vertical and horizontal transmission.