Transposon sequencing begins by transducing bacterial populations with transposable elements using bacteriophages. The major group of transposable elements in "E. histolytica" are non-LTR retrotransposons. Plant studies have shown that pan-genome dynamics are linked to transposable elements. Biotinylated histones play a role in repression of transposable elements and some genes. Somatic mosaics are common in embryogenesis due to retrotransposition of L1 and Alu transposable elements. The presence of transposable elements is another influential element of non-homologous crossover. The distribution of transposable elements is inversely correlated with gene density. The contribution of transposable elements to the genome is especially well studied in plants. Pathogenic tau can also cause neuronal death through transposable element dysregulation. The genome is very compact, and is one of the few organisms without transposable elements. Occasionally, genetic material not originally in the transposable element gets copied and moved as well. This age-dependent expression level of transposable elements is reduced by calorie restriction diet. The Ac and Ds elements share two properties that are common for transposable elements. As such, Ago3 piRNA lack the ability to target transposable element transcripts directly. There are different theories explaining the conservation of transposable elements.