With the discovery of meiosis-specific chromosome cores that form homologously aligned pairs, synaptonemal complexes (SCs), during the chromosome pairing phase of meiotic prophase(@, it was anticipated that there may exist a functional relationship between the cores and the processes of homologous synapsis, recombination and segregation. This assumption was based not least on the perception that the fairly universal occurrence of SCs in meiotic prophase cells of sexually reproducing organisms implies a significant biological function. An intuitive model would see the chromatin attach itself in a series of loops to the chromosome core, possibly at specific DNA sequences. The parallel alignment of a pair of cores would juxtapose homologous DNA sequences and thereby permit the initiation of rec~mbination(~) (Fig. 1). Summary Ideas about the mechanisms that regulate chromosome pairing, recombination, and segregation during meiosis have gained in molecular detail over the last few years. The purpose of this article is to survey briefly the shifts in paradigms and experiments that have generated new perspectives. It has never been very clear what it is that brings together the homologous chromosomes at meiotic prophase. For a while it appeared that the synaptonemal complex might be the nuclear organelle responsible for synapsis, but the supporting evidence has not been entirely convincing. Whatever the mechanism, it has always been assumed that homologous synapsis creates the opportunity for homologous DNA sequences to initiate recombination. At present, alternative ideas are developing. Attractive is the concept that double strand DNA repair mechanisms, that find and use the undamaged homologue for repair, have evolved into a meiotic mechanism for the recognition and pairing of homologous sequences. Subsequent intimate synapsis of homologous chromosomes in the context of the synaptonemal complex may serve later functions in the regulation of interference and segregation at first anaphase. A number of areas that are being tested at present and some that may be investigated in the future are discussed at the end of the review.