The transgene contains an enhanced green fluorescent protein, EGFP, driven by DEAD (Asp-Glu-Ala-Asp) box polypeptide 25 (Ddx25) promoter/enhancer sequences that contains a 5'deletion - 3.6 kb/-205 bp upstream of the promoter. GFP expression is directed to meiotic and haploid germ cells. (J:198206)