Fig. 1.

Pairing and recombination are required for the proper segregation of homologues. The 10 pairs of chromosomes in maize are depicted in late prophase of meiosis after successful pairing and recombination. Each pair has completed an homology search, and cross-overs hold together the bivalents in preparation for congression on the metaphase plate and separation in anaphase I of meiosis. Such pairing and recombination ensure the distribution of the homologues and prevents the production of meiotic end products with extra or missing chromosomes.