Prelude to a division.
Accurate segregation of chromosomes during meiosis requires physical links between homologs. These links are usually established through chromosome pairing, synapsis, and recombination, which occur during meiotic prophase. How chromosomes pair with their homologous partners is one of the outstanding mysteries of meiosis. Surprisingly, experimental evidence indicates that different organisms have found more than one way to accomplish this feat. Whereas some species depend on recombination machinery to achieve homologous pairing, others are able to pair and synapse their homologs in the absence of recombination. To ensure specific pairing between homologous chromosomes, both recombination-dependent and recombination-independent mechanisms must strike the proper balance between forces that promote chromosome interactions and activities that temper the promiscuity of those interactions. The initiation of synapsis is likely to be a tightly regulated step in a process that must be mechanically coupled to homolog pairing.
Bhalla
Needhi
N
Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA. bhalla@biology.ucsc.edu
Dernburg
Abby F
AF
D000818:Animals; D002503:Centromere / Q000378:metabolism; D023902:Chromosome Pairing; D020090:Chromosome Segregation; D002875:Chromosomes / Q000378:metabolism; D008540:Meiosis / Q000502:physiology*; D009685:Nuclear Envelope / Q000378:metabolism; D011995:Recombination, Genetic; D013573:Synaptonemal Complex / Q000378:metabolism / Q000648:ultrastructure