<i>trans</i>-reactivation is mediated by a diffusible factor.

<p><b>(A)</b> Upper panel; schematic representation of normal fertilization leading to the generation of an adult fly. Lower panel; description of the process of gynogenesis in which a viable adult fly that does not carry any genetic contribution from the father is generated through the fertilization of a gynogenetic <i>gyn</i>^<i>2</i>, <i>gyn</i>^<i>3</i> egg (where diploidy is restored by the fusion of two non-sister nuclei out of the four egg pronuclei which result from the second meiotic division) by a <i>ms(3)</i>^<i>K81</i> sperm (one of a rare class of fly male sterile mutations in which sterility is caused by the elimination of male pronucleus after sperm entry into the egg). Despite, the male pronucleus (blue) does not contribute to the zygote, the male nucleoplasm (light blue) contributes together with the two female pronuclei (pink) to the development of a gynogenetic adult fly. <b>(B)</b> Cross scheme used to test if nucleoplasmic factors devoid of any male genomic contribution coming from the <i>w* trans</i>-reactivating allele can <i>trans</i>-reactivate <i>w</i>^<i>m4h</i> in female gynogenetic adult flies. Possible F1 eye phenotypes coming from the cross are boxed. Eye pigment measurements of parental and gynogenetic progeny were conducted to score the presence of a <i>trans</i>-reactivated <i>w</i>^<i>m4h</i> in <b>(C)</b><i>w</i>^<i>m4h</i><i>; gyn</i>^<i>2</i>, <i>gyn</i>^<i>3</i> female, <i>w</i>^<i>sey</i><i>; ms(3)</i>^<i>K81</i> male parental stocks, and F1 gynogenetic <i>w</i>^<i>m4h</i>; <i>gyn</i>^<i>2</i>, <i>gyn</i>^<i>3</i> progeny, or in control <b>(D)</b><i>w</i>^<i>m4h</i><i>; gyn</i>^<i>2</i>, <i>gyn</i>^<i>3</i> female, <i>Δw; ms(3)</i>^<i>K81</i> male parental stocks, and F1 gynogenetic <i>w</i>^<i>m4h</i>; <i>gyn</i>^<i>2</i>, <i>gyn</i>^<i>3</i> progeny. Eye pigment quantification graphs have a different scale.