Patched (Ptc, green) is expressed in most cells of the Drosophila wild-type germarium including follicle stem cells. Hedgehog (Hh, red) accumulates on the surface of the apical cells. Germ cells are i...

Smoothened (Smo; green), a downstream effector of Hedgehog (Hh), is expressed in most cells of the wild-type Drosophila germarium including follicle stem cells, but is excluded from Boi- and Hh-expres...

In the absence of boi (boi[e] mutant), Hedgehog (Hh, red) is redistributed from apical cells to the extracellular space of the local follicle stem cell niche (CIL# 13744, 13745). Expression of Boi in ...

boi controls follicle stem cell proliferation. Germaria from wild-type in which germ cells (blue, anti-Vasa) and differentiating follicle cells (red, anti-Fas3) are labeled. Stalks between the germari...

boi controls follicle stem cell proliferation. Germaria from boi[e] mutant in which germ cells (blue, anti-Vasa) and differentiating follicle cells (red, anti-Fas3) are labeled. Stalks between the ger...

Scanning electron micrograph showing in vitro fertilization of a hamster oocyte. The sperm head, near the center of the field of view, is engulfed by the microvilli on the surface of the oocyte membr...

Scanning electron micrograph showing a lateral view of sperm penetration of a hamster oocyte during vitro fertilization. As the membrane of the sperm head fuses with that of the oocyte, the microvill...

In insect spermiogenesis, mitochondrial cristae disappear and a proteinaceous material is deposited in filaments that become closely packed paracrystalline arrays. In this micrograph, crystals are pr...

First cleavage of a live mouse zygote. Clear circles are the nuclei which are in a sea of granule dense yolk. The band around the two cells is the zona pellucida.

The Hedgehog (Hh) pathway is activated in follicle stem cells of animals lacking boi (boi[e]; this image), relative to wild-type Drosophila (CIL# 13756), based on activated cubitus interruptus (ci) st...