Abstract
In meiosis I, exchanges provide a connection between homologous chromosome pairs that facilitates their proper attachment to the meiotic spindle. In many eukaryotes, homologous chromosomes that fail to become linked by exchanges exhibit elevated levels of meiotic errors, but they do not segregate randomly, demonstrating that mechanisms beyond exchange can promote proper meiosis I segregation. The experiments described here demonstrate the existence of a meiotic centromere pairing mechanism in budding yeast. This centromere pairing mediates the meiosis I bipolar spindle attachment of nonexchange chromosome pairs and likely plays the same role for all homologous chromosome pairs.