Sisters dancing in meiosis

The life cycle of eukaryotes oscillates between a diploid and a haploid state; meiosis and fertilization alternate to generate the transitions between these states. Meiosis consists of two special rounds of cell division, preceded by a single phase of DNA replication. The most recent advances in this field were presented at the EMBO Conference on Meiosis, organized by Bernard de Massy and held at Isle sur la Sorgue, France, between 19 and 23 September 2009. The different steps of meiosis were discussed, including the generation of meiotic DNA double-strand breaks (DSBs)—which results in meiotic recombination and is associated with homologous chromosome pairing —and aspects of chromosome segregation and progression through the cell cycle. At the end of the conference, a session on genome evolution brought us back to the beginning of meiotic prophase, providing novel insight into the initiating events of meiotic recombination. Two key themes emerged from this meeting, in addition to other exciting talks that we do not have space to cover. The first novel viewpoint identified the dynamics of chromosome regulation between individuals or within single cells as important at every level of meiotic regulation—including the initial choice of where to form the meiotic DSBs—in addition to the obvious importance of dynamics associated with chromosome movements during pairing and meiotic divisions. The second theme involved the interactions that take place between sister chromatids in meiotic recombination and chromosome segregation.