Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12915-015-0148-y/MediaObjects/12915_2015_148_Fig1_HTML.gif)
Organization of the C. elegans hermaphroditic gonadal arm. A mitotic zone (MZ) contains stem cells at the distal end, which ensure organ self-renewal as cells are consumed proximally for spermatogenesis (during larval development) or oogenesis and apoptosis (during adulthood). Differentiation of mitotic cells is controlled by opposing factors such as FBF-1/2 and GLD-1, expressed in opposing gradients. The cell cycle regulator cyclin E1 (CYE-1) is expressed throughout the MZ. Subregions are shown that are considered in cell cycle analysis: distal-most mitotic zone (DMMZ), medial mitotic zone (MMZ), and proximal mitotic zone (PMZ). Cell position can be measured by the number of rows to the distal end (rows 1 to 19 are numbered)