Ectopic expression of toc in germ line cells leads to the formation of normal egg chambers containing a single 16-cell cyst. A large proportion of eggs laid develop into wild type embryos. The egg chambers are separated from each other by stalks of 10-15 cells, compared to 4-6 in wild type ovaries. The extra interfollicular cells are either correctly organised into a stalk or form a cluster around one of the central interfollicular cells.