The center image shows a large female oocyte that was recently fertilized. Although many sperm are present (Magenta) only one sperm is allowed to enter the cell (Red, upper right). In response to sperm entry, the female chromosomes (Red, left) finish separating in meiosis I, via a fibrous microtubule spindle structure (Green). After a second meiotic division and many mitotic cell divisions, this fertilized cell will develop into a young worm (as shown) in about 12 hours.
Research from the laboratory of Dr. Martin Srayko
Fertilization: A sperm-oocyte partnership that depends on effective communication. Upon fertilization, sperm provide not only genetic material to the future progeny, but a message that instructs the female cell to finish the meiotic divisions. The study, "Maternal MEMI Promotes Female Meiosis II in Response to Fertilization in Caenorhabditis elegans" has been published in GENETICS, and is featured in the commentary, "Parental Control Begins at the Beginning".