[The synaptonemal complex: a structure necessary for pairing, recombination or organization of the meiotic...

The synaptonemal complex (SC) is a prominent and evolutionaly well conserved structure which is strictly meiotic. Several evidences from mutant phenotypes support the hypothesis that recombination and SC formation are mutually interdependent processes. Moreover, the SC recombination nodules correspond in number and location to the crossing-over events. However, recent data confirm that SC formation does not require initiation of recombination, and several observations indicate that full synapsis is not required for recombination. The potential roles played by the SC will be discussed in the following framework: First, although not required for homology recognition, the SC could promote interhomolog interactions in situations where the normal processes have failed (interlocking, heterologous pairing, etc.); Second, polymerization of the SC components might permit the recombination process to progress by modulating the number and localisation of reciprocal versus nonreciprocal exchanges (i.e. interference) and; Third, the SC may play an important role in meiotic chromosome structure and especially in inter-sister interactions.