The dorsoventral polarity of Drosophila egg is established by means of signaling between the germ line-derived oocyte and the surrounding somatic follicle cells.

果蝇胚胎发育是由四种，别控制头尾、前、后以及背腹。

In the posterior segment, its dorsoventral axis was the longest, and could be divided into two parts: the dorsal and the ventral parts.

后段背腹径最长，可为背侧和腹侧，两细胞界清晰。