MaleReproFIG 18: Cell division in the germ line.
A. Nomarski DIC image shows locations of mitosis, meiosis and gametogenesis in the germ line.
B-D. DAPI -stained germ line cells. (Image source: J. Maciejowski and E.J. Hubbard).
B. Mitosis occurs at the distal end of the germ line in an area called the mitotic zone.
C. As germ cells move farther away from the distal tip cell (DTC), they enter an area called the transition zone where they enter meiosis I.
D. Cells proceed through prophase I to pachytene. Chromosomes spread out along the periphery of the nucleus forming a "bowl of spaghetti" phenotype.