Expression of wun2^EP2217 under the control of Scer\GAL4^{nos.UTR.T:Hsim\VP16} results in defects in germ cell migration in embryos. Expression of wun2^EP2217 under the control of both Scer\GAL4^twi.PG and Scer\GAL4^how-24B results in a strong and completely penetrant germ cell migration phenotype; the germ cells are repelled from their normal target tissue (mesoderm) and instead remain on the midgut. The number of germ cells is reduced in these embryos. Gonadal mesoderm develops normally in these embryos. The embryos develop to adulthood, hatch and are often sterile. Expression of wun2^EP2217 under the control of Scer\GAL4^twi.PG, Scer\GAL4^btl.PS or Scer\GAL4^48Y results in a decrease in germ cell number.