Fig. 4From: Pursuing the impossible: an interview with Tim HuntFrog oocytes before and after maturation. Oocytes (left-hand side) are surgically removed from the belly of a female frog and incubated in the presence of progesterone, which induces maturation. The white spot (right-hand side) that forms after a few hours marks the position of the second meiotic spindle, indicating completion of the cell-cycle transitions that occur at maturationBack to article page