In the animal world, if several males mate with the same female, their sperm compete to fertilize her limited supply of eggs. Longer sperm often seem to have a competitive advantage. However, a study conducted by researchers from the Universities of Zurich and Stockholm now reveals that the size of the animals also matters. The larger the animal, the more im-portant the number of sperm is relative to sperm length. That's why elephants have smaller sperm than mice.

Scientists at the Institute of Molecular Biology (IMB) in Mainz have unraveled a complex regulatory mechanism that explains how a single gene can drive the formation of brain cells. The research, published in The EMBO Journal, is an important step towards a better understanding of how the brain develops. It also harbors potential for regenerative medicine.