We aligned the 36 A. thaliana LTR retrotransposons from Repbase Update [2] database which belong to Copia group corresponding to genes encoding reverse transcriptase to obtain the structured motif M1 [2,5] M2 [6,7] M3. Rows 2–5 show the profile (the frequency of observing a DNA base in a given position), and the last row shows the corresponding pattern over the IUPAC alphabet.