Reporter of mdg1 element transposition. Contains a complete copy of the mdg1 retrotransposon (flanked by P-element ends) with an EGFP cassette inserted in the antisense direction in the non-coding sequence of mdg1. The EGFP sequence contains a disruptive intron that can be spliced during transcription of the retrotransposon, but not during transcription of EGFP. Thus, EGFP protein is only expressed after mobilization of the mdg1 element in the reporter transgene, which generates a new copy of mdg1 containing EGFP without the disrupting intron.