The function of retrotransposable elements in degenerative illnesses associated with ageing . Because neuronal cells are more open to retrotransposition , transposon insertions occur more frequently in brain than in other somatic tissues . Neurotoxic Substance Response Reverse transcriptases (TEs) are categorised into DNA transposons and retrotransposons (27). Many people are curious about the effects of active TEs on human brain development and illness because of the genetic diversity and mutations they can create . Genomes with an increased frequency of mutations and copy number variations (CNVs) may also contain transposition of retrotransposons (LINE1) caused by short telomeres .