Meiotic chromosomes: Integrating structure and function

Meiotic chromosomes have been studied for many years, in part because of th e fundamental life processes they represent, but also because meiosis invol ves the formation of homolog pairs, a feature which greatly facilitates the study of chromosome behavior. The complex events involved in homolog juxta position necessitate prolongation of prophase, thus permitting resolution o f events that are temporally compressed in the mitotic cycle. Furthermore, once homologs are paired, the chromosomes are connected by a specific struc ture: the synaptonemal complex. Finally, interaction of homologs includes r ecombination at the DNA level, which is intimately linked to structural fea tures of the chromosomes. In consequence, recombination-related events repo rt on diverse aspects of chromosome morphogenesis, notably relationships be tween sisters, development of axial structure, and variations in chromatin status. The current article reviews recent information on these topics in a n historical context. This juxtaposition has suggested new relationships be tween structure and function. Additional issues were addressed in a previou s chapter (551).