transposable elements
TEs seem to have complex regulatory functions and contribute to the coding regions of many genes.
The proportion of proteins with TE-encoded fragments (approximately 0.1%), although probably underestimated, is much less than what the data at transcript level suggest (approximately 4%). In all cases, the TE cassettes are derived from old TEs, consistent with the idea that incorporation (exaptation) of TE fragments into functional proteins requires long evolutionary periods.
Aa significant portion of eukaryotic genomes is composed of transposable elements (TEs). Given the abundance and diversity of TEs and the speed at which large quantities of sequence data are emerging, identification and annotation of TEs presents a significant challenge.
Subtypes
rolling-circle eukaryotic transposons (Helitron transposons) (#17850916#)
References
Wicker T, Sabot F, Hua-Van A, Bennetzen JL, Capy P, Chalhoub B, Flavell A, Leroy P, Morgante M, Panaud O, Paux E, SanMiguel P, Schulman AH. A unified classification system for eukaryotic transposable elements. Nat Rev Genet. 2007 Dec;8(12):973-82. PMID: #17984973#
Gotea V, Makalowski W. Do transposable elements really contribute to proteomes? Trends Genet. 2006 May;22(5):260-7. PMID: #16569458#