Pairing competition between metacentric and telocentric chromosomes in autotetraploid rye

Abstract

Pairing preferences have been analyzed in tetraploid cells of rye telocentric substitution lines where competition took place between telocentric and metacentric partners within each set. Chromosome arms in telocentric condition (bearing large telomeric blocks of C-heterochromatin) showed a higher probability of being associated at metaphase I. However, the excess of identical over homologous pairing found in most cases could not be ascribed to such differences in pairing (or chiasma formation) ability between homologues. Other hypotheses for explaining preferential pairing in polyploids are discussed. © 1989, The Genetical Society of Great Britain.