The germ line of an adult C. elegans hermaphrodite. (A) On the top is a drawing of an adult C. elegans hermaphrodite emphasizing the cells of the germ line. The gonad consists of two reflexed arms that meet at a common uterus. At the very distal end of each arm is the somatic distal tip cell (DTC; yellow). Germ cells near the DTC are proliferative (green). As cells move proximally, towards the uterus, they enter meiotic prophase (red). The first cells to differentiate are sperm (blue), which are stored in the spermatheca. As oocytes (orange) pass through the spermatheca, they become fertilized and begin embryogenesis (green). Below the diagram is a DIC image of one gonad arm in an adult hermaphrodite. (B) Illustrated is a summary of the tissues used to obtain mRNA for the germline microarray analysis , the soma SAGE library  and the germline SAGE library (this work). In the microarray analysis mRNA obtained from wild-type (N2) worms was compared to mRNA obtained from glp-4(bn2ts) worms. Germ cells in glp-4(bn2ts) animals grown at the restrictive temperature arrest in mitosis such that only ~12 germ cells are present . The somatic gonad is still present, but the gonad arms do not reflex back. mRNA for the construction of the germline SAGE library was obtained from ~150 hand dissected gonad arms. The gonad arms were dissected away from the body of the animal at or near the spermatheca. The soma SAGE library was constructed from mRNA isolated from glp-4(bn2ts) animals grown at the restrictive temperature.