passages.id: split_8_test_502_passage
passages.type: progene_text
passages.text: Although most non - LTR retrotransposons encode an apurinic - like endonuclease upstream of a common reverse transcriptase domain , R2 and many other site - specific non - LTR elements do not ( CRE1 and 2 , SLACS , CZAR , Dong , R4 ) .