TY - JOUR T1 - Meiotic Pairing and Segregation of Achiasmate Sex Chromosomes in Eutherian Mammals: The Role of SYCP3 Protein A1 - de la Fuente, Roberto A1 - Parra, María Teresa A1 - Viera, Alberto A1 - Calvente, Adela A1 - Gómez, Rocío A1 - Suja, José Ángel A1 - Rufas, Julio S A1 - Page, Jesús Y1 - 2007/11/02 N2 -
Meiosis is a special kind of cell division that leads to the formation of gametes. During meiosis the number of chromosomes must be halved in the daughter cells, and to do this properly, most organisms use an amazing strategy: during the first of the two meiotic divisions, homologous chromosomes associate in pairs, undergo a reciprocal genetic interchange, and then each member of the pair segregates into a different daughter cell. Genetic exchange, called meiotic recombination, is a key process to ensure that homologous chromosomes remain tightly associated until they segregate. In general, sex chromosomes are subjected to the same processes as the rest of chromosomes. But, of course, exceptions exist. This is the case in the Mongolian gerbil, a mammal whose sex chromosomes pair and segregate during male meiosis without undergoing meiotic recombination. We have found that they are able to do this because some proteins of a meiosis-specific structure, the synaptonemal complex, are reorganized to maintain sex chromosomes associated until they segregate into daughter cells. This kind of behavior resembles the situation found in marsupials and some insect species, indicating a recurrent role of synaptonemal complex components in chromosome segregation when meiotic recombination is missing.